*sighs*
The problem, Ashcroft, is that, as you might have noticed so far, is that we're bogged down by history and use it as precedent. In our case, "history" means about 7200 posts (or thereabouts) without an easy way to reference them or search them easily  and 7200 posts that will disappear soon, as LL is going to shut the forums down shortly (although that's another story).
Broadly speaking, the Constitution vaguely defines that the "Founding Philosophy" is part of the Constitution itself  but it doesn't explicitly refers what [i:30v605c1]all[/i:30v605c1] the Founding Philosophy [i:30v605c1]is[/i:30v605c1]. It thus places in the hands of the SC to interpret these aspects without a "strict adherence to the founding documents" (III., 
This naturally makes things way complex, but it was intended to mean that a certain flexibility in interpreting the [i:30v605c1]intent[/i:30v605c1] of certain aspects of the legislation and constitution were not only allowed, but encouraged.
You can quickly see where all this is leading...
It also means that every time someone questions a simple thing that was never codified in law, the poor SC members have to spend several hours painfully putting search queries into the SL forums search engine, hoping against hope to get those old documents back. Also, some of the things on the "founding philosophy" were lost forever; copies of those have been made, but the legitimate use of those copies are being questioned. Which makes everything so more fun.
Basically, the issue about the "powers" of the RA and the Guild, and how they relate to each other, were never defined [i:30v605c1]clearly[/i:30v605c1]. Also, the Constitution was written at a time where the land where the City was built belonged to Governor Linden, and we had only the option to [i:30v605c1]use[/i:30v605c1] it, not define [i:30v605c1]how[/i:30v605c1] it should be used. This naturally raised tons of questions and issues, and it also meant that the laws were never changed to reflect the new situation, except for some marginal laws to regulate the ownership of parcels.
One think that was clear, though, is that the RA proposes budgets to be approved, but that the Guild would hold the Treasury (and a way to veto the budget). This separation of powers was necessary  the ones that have the money can't do anything with it without laws; the ones that make the laws don't have the money.
As time went by, a new balance was found  all unwritten, all only posted here and there at the forums. The RA does the overall strategic planning; the Guild implements it in terms of providing infrastructure and services. In other terms: the RA approves (and roughly oversees) the way the urban planning should be implemented; the Guild builds it.
It's also the Guild that verifies new citizens, writes out the deeds, assigns the plots, and has all Land Managing duties. The RA oversees the whole issue. Again, there are no specific laws on that. What was assumed is that the Guild, since it need access to the buildings (in technical, SL terms), does the job of maintaining the city. Again, this was never codified.
Now since this is not codified in law, it's only an interpretation, which can change.
However, it is a [i:30v605c1]crucial[/i:30v605c1] interpretation. Nothing prevents, under the current model, that the RA simply removes all the powers from the Guild  lawfully ones, or ones inherited by historical reasons  and places them in the hand of a Dictator or Tyrant to speed up the process 
They [i:30v605c1]could[/i:30v605c1] do it, and nothing would strictly forbid it, on pure philosophical terms  "what isn't written, does not exist".
Sadly, the Dean of the SC also has a conscience and a responsability. I personally view the inability of the RA to pass a large amount of laws to address [i:30v605c1]all[/i:30v605c1] the issues one of the weakest points in NFS. Too much is left unsaid and unaddressed, and "lost" in comments on forum posts, never to be codified. However, that is one limitation that the RA has to address "somehow" (having an executive, for instance, would certainly improve matters very much, by separating mere administrative tasks from the more important discussion on overall frameworks).
Despite that limitation, it doesn't mean that things are not "worthless" just because they were never put into law; it just means that they are proto-laws, waiting to be codified, and put into hold until someone has time to go over them. Personally, I think it's a good time to do it [i:30v605c1]now[/i:30v605c1].
Sooo if from a literal, strict interpretation of the tiny Constitution, the proposed model for the new executive is not going to conflict with anything under the Constitution, in practice it overlaps several issues that are being handled by the Guild.
Now, the Guild, as you know, does not have any procedures, just a few guidelines and ideas (like the ones for the Treasury). It doesn't publish a journal; it is not overseen by any external body. They are not required to do so, either; and it's left unsaid if the Guild can even create those procedures, or if the RA has any authority inside the Guild at all.
Under this legal vacuum, the Guild had to work within its own constitutional limitations; it was generally a good practice to allow them some leeway in the way they dealt with "providing infrastructure and goods". The RA plans; the Guild provides.
Since the Guild was mostly created to have the artisans have a strong voice in how the city should look like, it was generally felt best to allow them this leeway.
The new executive (under all four proposals) will thus change the relationship with the Guild irrevocably. It will mean that the Guild will have a much more restricted role. The executive apparently will have the power of defining and overseeing land use, expend the money directly under the RA's supervision, assume the role of the Chamber of Commerce (currently under the Guild), and enforce the guidelines defined by the rA.
All these are currently done by the Guild, even if codified explicitly.
It is my understanding that  while fully supporting this concept of an exective!  it should be made clear that the Guild's powers are being defined, once and for all, and that these should be made much less important. Changing the relative weight of the three branches is indeed a constitutional issue. You might have noticed that the proposed "Burgermeister Acts" only establish a clear relationship between RA and the Executive. This is naturally so, since effectively the RA is delegating part of their powers into the Executive. But it is also delegating [i:30v605c1]new[/i:30v605c1] powers (or rather: old, uncodified powers) into the Executive, [i:30v605c1]without[/i:30v605c1] defining the relationship with the Guild.
So, in my understanding, more has to be done. First, a definition of the Guild's powers needs to be addressed  and I fear that you can't do that without touching the Constitution somehow. Secondly, lots of existing institutions have to be dissolved  no more Chamber of Commerce, for instance, and even the Treasury can be questioned ("to expend monies held by the Office of the Burgermeister of Neufreistadt for the administration and management of public facilities").
Why didn't the Guild need constitutional changes to "absorb" those institutions? Well, mostly, because the issue of dealing with financials was delegated to the Guild, by a loose interpretation of the founding documents and the financial veto on the budget, which was interpreted as meaning that the intent of the founders was to give the Guild the financial powers, as well as dealing with all service providers in NFS (thus, the Chamber of Commerce, as an association of merchants, was created under the Guild).
By removing effectively all those institutions and place them under the Executive, I feel that a bill is not enough. The whole concept of checks and balances is put into question. The RA is effectively placing all financial burdens under its own self. Again, I don't disagree with that  I only disagree that "only a bill" should be enough.
And we have two precedents to put a stop to this. On two occasions (once even under my own term as LRA  and one on the previous term), the RA tried to pass a law that created a "Financial Committee" to assume the responsibility of "advising" the Guild in financial matters. The reason for the veto was simple: the RA [i:30v605c1]cannot[/i:30v605c1] interfere in financial matters. Ever. It can only vote on the budget. The precedent was established  twice  that a single bill is not enough to remove any financial powers of the Guild and place them on any other institution.
Being true to the past precendence established, the SC will have no option but to remain true to its past rulings, and demand a constitutional change to allow the RA to change the balance of powers between itself and the Guild.
To avoid this  and since some people seem to be so reluctant to change the constitution  the Guild could, in theory, write a "joint statement" that delegates all financial powers to this new executive, by its own free will. Since the Guild's "statements" are not laws, the SC cannot pronounce on those. But as you see it would make things messier...
