this is the closest I think I can get to define my problem. I'm an interface designer and now I'm working with a team of programmers to develop a new CMS for a heavy media site. I'm sorry if it's a very, very dumb question to ask here, but I really need some help.

As I've started developing a specification list for a prototype it turned out a very big one. I do realize now that the client-side will be JS heavy, with lots of DnD and other "cool designer stuff". The CMS will even include a small project management system for its users, nothing big like Basecamp, but with a live feed of comments etc.

The problem is the the team has now separated. Someone is proposing the existing backend solution used in other CMS, someone is proposing to rewrite everything from scratch. The point to keep the code is that it is faster, the point to rewrite is to make it better for the proposed design (include Node.js and other stuff I don't actually get).

The question is — can the UI specs influence back-end? The guys that propose to use the existing solution did everything with the Yii framework (as far as I know), and they say that everything on server is not affected by this "interface coolness". Others say that it does, that even autosave can't work without server load.

Please, if this is really incomprehensible, again, I'm sorry, and I'll happy to clarify it after your questions. Thanks in advance