How will this revision affect the character/colour of the A12? (i.e. more or less coloured sounding).
Less.
From rummaging around online I understand the Pacifica is kind of halfway between the API and Neve characters.
Keep in mind that we're not cloning the Pacifica. We're offering a different choice of parts for the A12 that should appeal to people who like the Pacifica.
Is this revision something that will attenuate that distinctiveness?
The differences will be subtle, but it won't sound like the current A12. It'll move the characteristics a bit more toward the J99. The current A12 isn't going away, so it will remain an option.
Will it make the A12 more tweakable?
The A12 is plenty tweakable right now. The new options will use exactly the same circuit board.
Will it change the price of the A12?
Don't know yet what the new version will cost. Perhaps slightly higher, but we haven't settled on pricing.