It is going to be really hard for them to come up with new ideas because they have covered quite a bit in the three we have:
1. WHM: Has really good single target healing and really good AOE Healing.
2. SCH: Crappy AOE healing (better now though) and lower single target healing but with shields.
3. AST: Can do both of the others but not quite as good as either. (although diurnal is pretty kick ass with all the changes now)
What else could they do? Better AOE healing would be way to OP. Better single target would not be the way to go either. You couldn't go that Bleed healer that people are talking about or they would not survive mechanics in raids...unless they change how they are doing fights completely.