Well it doesn't help that enchantment and illusion spells, like many CC spells including most druid CC spells and utility spells like Dancing Light are crippled by a nonsensical concentration mechanic, and they consume spell slots regardless of whether they pass a save or not, and unfortunately most saves in this game are DEX or CON saves, of which mobs are high on, plus all the bugs people have mentioned like checks taking place both at the beginning and end of a turn, and how drastically the duration of CC was reduced on top of being crippled with the concentration requirement.

Then there's the Jump garbage making so many of the static environmental CC's like vines useless. You can drop a spike growth or vines or a Darkness, and mobs can just trivially jump out of it in one turn, or if an aoe like fireball goes off, it burns ut the vines or spike growth without at least some combination explosion bonus to account for the fact that a spell you wasted a spell slot on and was bound by concentration was erased from the battlefield.

I really hope they do a spell balance pass and look at Haste and how it works with actions so it doesn't just duplicate martial extra attacks. They could even do a half damage fall off on chain lightning, but let's be honest it's a two-three spell cast per long rest if you got the legendary staff only or the very rare Act 3 staves, otherwise it's one spell cast per long rest. And it would only nerf the single niche you would want to bring a spell caster over a martial class.

I also don't think spells should be gutted just because they made metamagic as a sorc mechanic so incredibly stronger than the other casters. Blanket nerfs to spells affecting already garbage classes like caster warlock make no sense, so if you gotta nerf something, you could just apply a damage fall off to the metamagic mechanic so if you duplicate the spell or cast another spell as a bonus action, they do half or a third of the damage of the original spell. Then balance the spells from there.

And give druids a proper spellbook with Bless and Chain lightning as a lv6 spell while Spore Druid should get Dethrone alongside Necromancer. Some spells like Cure Wounds and Healing Word also need buffing, because they're really bad unless you got a Life Domain cleric passive propping them up. It's crazy how much better tossing a potion is for heal quantity than a freaking spell that takes up a spell slot plus an action/bonus action. The Spores spells for spore druid also need numerical buffs, they fall off in Act 3 really hard, a 2d8 in Act 3 is just pitiful, and being unable to turn off spore clouds while these clouds affect NPC's and can turn them hostile is dumb, so make them not affect neutral NPC's if you can't turn them off.