Tactician is super easy even without using exploits. I'm playing with 3 friends with a far from optimal party and i don't remember us reloading any fight past level 4 (we are now level 13). And i watched playing my brother solo and his fights are a joke with a 2 caster/2 physical party. He AOE breaks magic shields in one round with one caster, then ccs them with the other. And we even outruled totaly broken cc like charm, chicken or medusa head.
I can imagine the game being hard if you are using wrong talents and skills. But it's hard to not use them, as nearly half of the skills are overpowered and need rebalancing.
If you are really having problems, just have points in polymorph on everyone + one summoner, have chicken, invis and chloro bomb on every character and charm on some. That alone should be enough to break the difficulty.
If you still want the game to be even easier, have someone take nekro and use the combo death wish+living on the edge+permafrost for up to 99% damage increase. Elemental affinity on your casters lets you use spells worth of 12 AP in one round. Try to get evasion (through items or skills). Further you could use teleport and netherswap to control the battlefield. The combo chicken with rupture does insane damage (if you have a scoundrel). I can't even imagine how easy the game will be if played this way.
And don't waste any points in wits, it's useless.
