I don't have much problems with ACA's or Blizzards, that said, my 1232 locks up when I insert my transfer card in the PCMCIA slot.
It seems Blizzard PPC's and Apollo's run best on 1B boards, my 1230/56 ACA's are both on 2B boards and also run fine.
Blizzard 1230's will work on all of them, most of them have 32 MB which is more than enough for games.
I've encountered the most problems with ACA's on 1D4 boards, so these do need timing fixes if you want to use a board like that, so to sum up:
No not all boards need timing fixes when you pop in an accelerator.
And like they say, if it ain't broken, don't try to fix it.
Also when using ACA's keep tweaking with WHDLoad and ACA parameters until you got it stable.