We'll just have to live with that for those satellites that have already been designed, but for future designs a linear transponder seems the obvious choice. A 40 kHz linear transponder would allow for multiple SSB QSO's over areas with a high Amateur population but would still enable the use of FM in the many areas of the world where there are few Amateurs.
This is a good idea, as demonstrated by VO-52 where hams in South Asia are encouraged to try it in FM and the rest of us are to use SSB or CW. But don't overlook the interest in FM satellites for the areas with high ham populations, also. Otherwise, there goes a low-cost entry to amateur satellites in those areas. KiwiSAT is interesting, in that it will have an FM repeater and a linear transponder.
I think Patrick raises an important point here. The FM sats are a very good entry point into satellite operation.
I got into satellites as a result of seeing just how easy it was to make contacts on AO-51 with a radio shack HTX-242 and an FT-817 that I already owned. Since I have been bitten by the satellite bug, I've gone out an bought an FT-847 and pre-amps, and I will hopefully be putting up a better antenna array soon to help with linear satellites.
If it hadn't been for AO-51 and its "Easy Sat" reputation, (helped along by K7AGE's videos on YouTube), I probably would have never gotten started and kept on thinking satellite operation was "too hard".
-- Sean - VA5LF