What most fans of the old shows seem to want is what happened after TNG, DS9 and Voyager. I (and probably many others) had an idea for a TV movie / miniseries format which although very fannish, could've been workable-
Teaser - NX01 Enterprise has a brief encounter that has a knock on effect over a hundred years later. Fast forward to post Nemesis - an issue from the past affects Starfleet, in the course of its resolution involving some personnel / cast from ALL of the old shows, including some flashbacks to TOS or movie era Trek done with old clips and new CGI (as in Trials and Tribble-ations) as Kirks crew had had a similar encounter, since highly classified.
This sort of approach has worked nicely in the novels on multiple occasions and would easily accommodate fans of each show.
Unfortunately, all the sets have gone and it would now be hugely expensive and would probably only generate poor or average viewing figures...