Well about the last question I can certainly tell you that most gear in this game drops randomly and you can theoretically get it anywhere in the game, but farming on higher difficulties and stronger enemies definitely helps. Also best gear in the game requires you to be around level 94 and will only drop on ultimate.
About a fun caster that kills quickly, I was always a big fan of AAR (albrech’t aether ray). Sure it does require a lot of energy and energy regen to sustain the ray, but as a caster you should aim to have a lot of those anyway. Plus from what I’ve heard AAR is getting buffed soon (or was it already, sorry I’m not sure). Also sorry that I cannot tell you the specifics right now, just search the build compendium and I’m sure you’ll eventually find something to your preference. I had a lot of fun playing a chaos ray warlock back in the day, but that was prior to my switch to hardcore, and I deleted all my old sc characters.
But yea she was very fun to play, definitely one of my all time favourite characters. Also some people will tell you that casters are not tanky, that’s not true, a good caster will also have a very high dps, plus can usually kill from range reliably. Certainly some bosses can be a pain, but most are not. As an arcanist you definitely have a couple of skills that help a great deal when tougher enemies get closer. I’d even go as far to say that casters can be a bit safer in certain scenarios. I remember having a very few deaths on that AAR caster, and even most of them were a consequence of me fucking around with mogdrogen when I really shouldn’t. Between Maiven’s sphere, mirror of ereoctes and mostly killing from range you are mostly pretty safe.
I actually thought of building a mage hunter a little while ago, my very basic premise was using AAR from distance while under maiven’s, inquisitor seal and with WoR handy. I could only imagine how that character would have to work pretty if not very well. This was some 2 minute theory crafting, I bet you can make something way better with grimcalc in 15 minutes max. Just giving you a basic premise for what I think should probably work very well. You would mostly just spam rightclick while buffing yourself, you can bind some damaging devotions and heals to certain skills, I really don’t remember having to press a lot of buttons with my warlock back in the day. On the contrary, I’d say it was more of a caster equivalent of a forcewave soldier…
So yea if you want a very easy to play caster, definitely go with AAR or at least some type of a channeled skill, I can think of drain essence in necromancer, but I honestly don’t like that skill purely from personal preference, also I currently have no idea how to theory craft around it. Bottom line, just try to build around some type of a channeled skill that will be your main dmg source, then just try to build up your sustain, RR and all the other usual stuff. I am honestly not sure about OA on casters though, I would just put everything into phisique and max your usual spirit and energy skills in arcanist.
Ok that’s what I found in build compendium:
http://www.grimdawn.com/forums/showthread.php?p=591897#post591897