I've removed summon from every mob in Icewell except Dain.
We're currently implementing alternative mechanics to handle ranged fighting, anti kiting and other things so that summon will not be as common or required throughout the world. We're also going to lower the frequency of summon for trash compared to bosses (we're implementing a few features and tools now that'll let us differentiate between npc status enmass).
We may look into VT encounters in more detail. Just take into consideration that we didn't create these encounters so it may be more difficult for us to really fully understand the reasoning behind every decision made with these.
I do remember Fevarn in Nadox. But I also remember really needing our ranged dps in the very next fight because we didn't have 5 tanks

I also remember a certain Dragon that demands magic damage in ToV.
If silence is excessively utilised and cannot be avoided in VT then there's room for us to change it. We'll try to get to it at some point.
We think actually balancing the classes for damage and utility takes priority and we're going to be doing that soon (we're doing a pass on each class as we do the 3.0 quests, which is my focus right now). That includes wizards and probably removing the idea that some of their spells can hurt the wizard.
We may need your help with some classes, both with ideas and with testing so we'll include you all in that when we get to it.