The game right now is balanced when the gear level is similar.
A lot of people crying about crit when there is much more defense to be gained (in 9 out of 10 cases of complaint):
1. Phys Resi - Most people either are not wearing any stones in gear or rings, or are wearing low lvl stones. I understand in a lot of cases you dont want to use lv6 ring spirit in 1 slotted uniques, or are "cheesing" lvl/pvp by not stoning phys resi. These things are what you are choosing to do, all while the crit stat is fully available (rings gloves weapon etc etc), of course your going to be 1 shot.
2. Crit Resi - Again crit is "fully available" so this is quite important, but it is able to be obtained the same way anyone else will get it. Meaning that the critter himself/herself is also looking for this very same stat/gear. Once you get this stat to a certain amount, it is way more OP in comparison to skillblock vs skills. Skillblock is 80% cap effectiveness, Crit resi work every time. In a fight where both have this crit resi item who wins?
3. Dodge/Block/Defense - The Dodge stat I agree is rare to find on items, but again I have seen elite give 15% that is not from fortune gate. Block a little more available yet without being 83 for gadius it can be lower for a non shield user. Yet there is always regular defense stats that many people forget counts too! I know there is ignore defense, but those gloves are also in the lotto and so are the weapons (harder to get)
So in the end, nah I dont think cast needs a buff. If you can only imagine both on crit resi you see how the balance switches to the caster favor, every crit the caster takes will be nullified and if he have nice hp the critter cant kill him.
Also you can think about HH tops and what they do to caster vs critter balance, its the same thing.