Honestly me too. The problem with this is that in order to make a toolkit interesting, the content itself has to necessitate it's use. A lot of the healing and support skills involved in a healer kit tend not to be necessary unless doing optimized runs for damage, that's just the way that fights are designed to keep them accessible. In order to make this happen they would need to make midcore content harder to heal, and when that used to be the case people just wouldn't play healer.
Ultimately they made fights easier to heal so that more people would play healer since that's always been a problem. The mentality of player that makes a good healer is rare in the gamer demographic, it's been the problem with support roles across most games for ages.