I don't know if devs reads my words, but in the hope i write here my suggestions.

I deeply love ailments system in this game. I think is the most complex and complete damage over time existing in arpg.
BUT, there is ever a but, isn't exploit. Ailment/dot system is simply an addiction to direct damage system: shot enemies with direct attack and do more damage with poison/bleeding etc. etc.

In this form, for me, is a waste of potential.
Create some skill that give ONLY indirect damage, that allow to proc dots and give us possibility to play only with ailment/dots.
For ie: plagueburst is an awesome aoe skill because it apply ailment to a large number of enemies BUT if it kills all for his explosion, is useless that apply dot. Enemies die for explosion not for dot.

This mixed system don't work and dots are ever outclassed by direct damage. Separate damage system in direct and indirect, complete damage and dots.

A good summoner class could mix this two aspects creating a necromancer/turret summoner (maybe ever demons if lore allows) that do damage with pets and indirect dots.

Thanks a lot