Well it is a relatively interesting concept, I'll give you that. It does bring up the point that the next healing job can't really be a "shields or hots" deal like AST is and will likely require a separate healing system.

The biggest problem with this concept isn't skill-based, but lag-based. Ever try to play NIN while lagging? Try casting mudras while your severely lagging, and then ask yourself "should healing abilities really be like that?" because at least with standard healing, you can just hit one button and at least the tank might still be alive. With a mudra-style healing setup, you might not even have the luxury of the thought that the cast went off.

The other complaint I have is more a personal taste in that I think the "rune" concept gets overplayed, but that's just me.

I'd like to see this concept more elaborated, but bear in mind that lag factor for that mudra-based healing aspect.