Well, how healers can be rewarded...
For example they are given healer specific things to do, and just not be a target for a split party stack.
I.e. add more cleanseable things, add actual healing not tied to just party taking damage like dragon heads in Shinryu EX or something. Maybe add "negative" health that needs to be healed, before health can be restored normally.
If all of that is too complicated, then i dunno.
As long as fights in the game will continue to be "sustained single target damage DPS checks" and the most important metric to overcome that is DPS, nothing will change.