25s already receive a multitude of incentives to compensate for their slightly higher logistical (i.e. outside of raid) requirement.
* More drops per kill.
* Higher chance of raiders being able to actually use the loot than in 10m.
* Much, much less executional (i.e. inside of the actual raid instance) responsibility per person.
* Multiple battle rezes for longer progression attempts and easier kills.
* Slightly less tightly tuned enrage timers on both normal and heroic modes than 10m.
It seems to me that if people still don't want to do 25s with so many incentives as it is, maybe 25s should simply be brought up to be even with 10m. Give them the same drops per boss, give them the same increased difficulty as 10m, take away their extra battle rezes and even though they still have a distinct executional advantage maybe people will actually take them seriously enough to want to try them again. As it is now most 25m encounters are an under-tuned joke.