4)Absolutely broken consumables. First of, why do elixirs last until long rest. I can literally pop giant elixir and not make long rest until the next act. Elixirs that last until long rest should be balanced. Potion of speed is also very unbalanced. It shouldn't give a spell classes second spell to cast, it should not give 2 more attacks, it should not exist at all. The nice way to balance is to make it last for 1 turn , no need to explain why here.
5)Broken stealth(as always), summons and other spells. I want to start with summons here. Why do summons not require concentration?Them not requiring concentration makes it no brainer S tier spell and you always use it after long rest and they last until... LONG REST. Like serioulsy who made this . Summons are very strong in this game and having them last until long rest with no concentration makes it very stupid. And on top of that you can have multiple of them. This should be balanced for sure .
On the Elixirs they should last 1 hour which I think Larian felt was enough to count them as Long rest from a "battles fought perspective".
On Summons, a lot of summons don't require concentration RAW. Planar Ally and the Animate, and Create Undead spells. Larian just extended them to the Conjure Elemental/Woodland being spells for consistency and restricted them to Wizards/Clerics, and Warlocks in most cases - which is also RAW. Sorcerers don't get summon spells at all, unless they exploit the game and Multiclass into 1 level of Wizard.
As for the rest I mostly agree, Tactician is too easy. The AI needs major work.