It's interesting that this problem doesn't really exist in act 1, is borderline acceptable in act 2 and gets really bad in act 4, where the situation in act 2 (long shopping trip 2-3x per level, as you go) turns into "oh I reached level 21... now it's time for 4-5 / level 22... now it's time for 6-8 restocks before I continue".
The terrible supply situation is a real fun-limiting factor and I think that this is not the intended balance, because it can only be mitigated by not having fun (= waiting for restocks).
Also I think that just decreasing the delay between restocks wouldn't really solve the problem, because the extended shopping trips would still exist.
And this also wouldn't solve the serious devaluation of unique items (something which I also dislike, because I think that if you get a very good unique item you should be able to use it until the end of the game, not just for one level - or, in many cases, not at all).
We didn't even touch lucky charm, yet... it's ok to have a vendor trash creation tool, but it would be really good if it gives items @ character level, not at supposed area level. I have a hard time remembering if I ever used a lucky charm item past level 3 or 4.
I just wish there was a big itemization / crafting overhaul. Together with the wasteful spending on talent points and civil abilities (which I mitigate by using the "FortJoyRespec" mod after gathering the companions, but this feels a little "cheaty") this would be something I really hope for.
Imagine no more "restock waiting", "throw away uniques" and "mindless scanning through the vendor inventories", but getting items which scale to your level, can be upgraded with +stat and +skill and, maybe, even transmogrified... this would be something.
In theory this could even work like this:
1. Your tank gets that nice unique sword from that semi-hidden area near Braccus Rex' statue on the beach @ level 4
2. Level 7: your tank wants necromancy, too, to become a blood drinking death knight and can add, via a nice process, "+1 Necromancy" to that sword as well
3. Level 9: Wow, those gloves I stole from that dwarf chick have +2 thievery... I want that on my +strength gloves... no problem! lets destroy the gloves, thereby getting 2x "essence of the thief" (or something similar) and use that to enchant the gloves I wear!!!1
(Extra result: no more armor pieces to swap out for... ahem... artisanry
... makes the game also much, much smoother to play!)
4. Level 11: oh, that sword from that vendor (white quality) looks nice, I want the stats from the unique I got but the looks of this vendor sword... lets transmogrify!
5. Level 17: the sword now is perfectly fine for a level 17 character, has been upgraded to, say (+/-) +2 warfare, +2 necromancy and it has an enchantment which makes it glow in red
6. Level 22: DING!! you just reached endgame character level... now lets see if the party can do a last enchantment on all the items before we kill those satanic scumbags who torture and enslave sourcerers... yes, it's possible... level 22 opens another slot on, lets say, head gear (either a +stat or a +ability or even a +skill slot)
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Overall balancing idea: if you're a completionist, like me, you should be in character level divine quality gear at the end. If you simply play the story, without many sidequests and without a divine order killing spree before engaging the Doctor and Lucian, you should be in character level gear with an average quality of the third best tier (dark purple?).
May sound extreme, but there should be a real advantage for completionism over just rushing through. Not doing sidequests and not taking care of the balance between good and evil should be punished by not getting best quality gear.
Because the more you do the more crafting materials for item upgrades you should have. Item level should automatically scale with your character, so you don't have to worry about shopping (and, therefore, being punished by having your fun interrupted) with every level up.
