Sounds good. I'm considering to play Tactician but I'm not sure I will be able to master it. I did not try the first game. How much you had to optimize? Had all equipment to be the very best for example? Partly I like to choose items for the look.
I also wonder what Honour mode will be like.
From my experience off running it through with my cousin, the mayor things we did were:(We did never play a lower difficulty, so I can't comment on the changes.)
1) Focus on good positioning on combat initiation, this was particularily important for bossfights where the boss had aoe attacks.
2) Run a lot of cc, Just overall important, you want to cc as much as you can, (either specific enemies, or spread out) and deal with the dangerous enemies first.
3) Get some movement skills on appropiate characters. Like the "tank" character had a charge for example, the rogue had haste and power stance (give +movement) to help us reposition during the fight "cheaper".
4) Use crafting gear, we discovered crafting gear around level 8, and it helped us a ton, just being able to keep weaponry "up to date" with your level irrelevent of drops was a huge boon to our damage output.
5) Make sure every character had potions.
Could be seen as a bit of a minmaxing thing, but we made sure every character had 4-5 healing pots (medium and large) at all times, were pretty easy to craft, and when your heals are on cooldown, they save lives.
6) Make sure we had some synergy between our characters.
While we didn't make the perfect minmaxed builds we did try and build complimentary characters, so my cousin played a dualwielding barbarian, and I played a stun and freeze mage. (Dual wielding with power stance has a high miss chance, high damage output, but you couldn't miss cc'd targets in divinity 1)
So that's more or less it.
TL;DR You are probably, expected to minmax a little, make sure you're well equiped, and that your positioning is on point, otherwise, any reasonably synergistic "builds" ought to work.
Of course the more minmaxed (powerfull) your characters are the less you have to care about the other aspects, as well. If you have a character capable of jusdt one turn killing a boss your position is sort of irrelevent.