Honestly, my only major gripe with the current system is that the more you optimize toward completing end game and HM content the more it forces cookie cutter builds as you slot things you don’t really want just because of the synergy or skill line passives.
I don’t really want to see players restricted into well defined rolls, but I would like to see class skills tuned so that they’re more desirable. I think this would go a long way towards reinforcing class identity.