I mean the problem is not freeze or cmww, or perma wotb.
they can certainly change things without touching player gear
you can engineer around the issue of perma freezing/perma cc immunity with
a) new affixes. those that specifically ignore (freeze or perma wotb).
eg: teleport bombs, polymorph, globes of darkness, distance manipulation, dispel player buff, reflect debuffs (you freeze me, you get frozen). slow bubbles, remove inertia, anti teleport barrier, zone of no winds. negate lifesteal, disarm skill (via a massive cd: any skill in your skill bar can be inflicted with this, if cmww and WW gets hit..time to run) , zone of even less proc rates (which would reduce crits to 1/10th of what you have) etc
b) better mob ai.
imagine an elite pack with 4 affixes, but controlled by a player, encountering a cmww.. wtf would you as a player go to the cm wizard only to be frozen.
you would probably split out, maybe run to gather reinforcements from ranged attackers, when using affixes against the player, you would definitely want to surround yourself. if you have teleport or ability to run, you would definitely teleport then snipe at the player from range everytime he came close.
c) strength of many buff only applies when you are near the party guide. anyone soloing away from party members generally get no extra buffs.
d) tagging of monsters = lasts 6 seconds before its untagged (For loot purposes/xp purposes)
e) allow teleport to other players in combat instantly (like marvel heroes)
if you want to gear around possible nerfs, then gear such that your gear can be mostly reused on a COB WD.