I thought I would try to restart with a positive outlook, and play through the Black Pits campaign while waiting for the BG2 patch. I'm afraid it did not help.
First, it was not entirely obvious how to import my party from the end of the first back pits. Eventually I started a new BP2 game with the default party, skipped through the intro as fast as I could while trying not to read the story, just to create a quick-save so that I could see where to try to import my BP1 save. Copied my final BP1 save into this directory, and still no 'import' option. I tried loading this as a saved game, and instantly crash to desktop.
So I give up on importing the game, and try to import the characters individually - but the 'import' button still cannot see my save, only the regular BG2 saves I have already imported for the main game.
Finally, I reload BP1 and manually export each character file from the end-game save, copy those over into the BG2 characters folder, and finally manage to import each character. The first thing I notice is that each character gets an upgrade to 600,000xp (apart from my cleric/thief whole already had that) - this is nice, but it means wasting 300,000xp on my Avenger druid who was supposed to dual to fighter at 12. So I head back to BP1 to try to dual him before import to make the most of the game - only BP1 crashes every time I try to dual-class at the end-game save. Not crash-to-desktop. The mouse still moves, but the keyboard is unresponsive, I cannot even close the game. My only recourse is to hold the power switch for 5 seconds to force a hard reboot.
"luckily", I have a very similar character already imported into BG2 who has dualed, and not yet reached 600k xp, so I choose to import him instead - only now I am missing the kit my druid had at the end of BP2, including the ring of Sune and Belt of Giant Strength. So we are back to BP1, transfer the kit to another character, remember to copy that exported character back to BG2 directory, and repeat the import process again. I skipped a few frustrating steps where I was learning all this, but all told after about 3 hours I finally have party I want to import into BP2.
Naturally, the first fight is rail-roared and I immediately lose all that kit I was so frustratedly trying to import accurately - but at least I am in the game.
Finally, I can head over and loot the locked chests for my starting kit - oops, no I can't. My Cleric/thief is not allowed to switch to his 'alternate' skills page where he can pick locks. That's OK, I'll use a key-binding? Nope, that won't work either. Darn - well as my emergency fall-back my Sorcerer actually did take Knock as a spell for emergency use. Ah, but we have a 100% spell failure effect, so can't go that route either.
The game might run smoothly if I get my strongest fighter to repeatedly bash the chests with his bare hands, but I won't find out. 3-4 hours of nothing but frustration mean the game is not fun like this. It is time to retire and wait for the patch again. My only consolation is that I don't think these issues are unique to the Mac App store version - I believe these problems remain unaddressed on the other platforms too.
I'm going to fall back to my original plan which is to come back in November, 1 year on from the release (23rd November). I had hoped to have at least the first patch by then (the one released to other platforms in the first week), but as the time till that anniversary is roughly half the time already given to public testing on the road to the BG 1.3 patch, and apparently we must simply wait for the next mega-patch for BG2, I am no longer optimistic.