4. In all fights, buff the damage of ranged enemies, but give melee the chance on hit to cripple/blind/etc. for several turns.
Depending on the fight, you would want to take out one or the other first. Gives you a choice with significant consequences for how the battle will play out.
No, this is precisely
not required. Skeleton archers are already vastly unbalanced for their levels. Their damage output,
compared to their melee / mage companions is already far higher.
For reference, a fight that isn't mentioned much is the 4 stone guardians, which is badly designed because its difficulty relies purely on the party build you have. 100% two turn petrify x 4 will wipe a melee focused party; however, if you have summons to soak up the effect, you can then use ice wall [on stone enemies? slow at most, surely?] to freeze x2 and split the encounter into two parts.
It was an interesting fight, but I can see it being impossible with certain parties.
The issue at the moment, even without duping them, is that summons can double your party size, and the ice elemental's special is > anything else. Fire elemental gets... flare. Whoo-hoo. (From memory of the alpha, air got elec, earth got boulders?). Adding to this, melee chars can spam x3 trips / knockdowns in a single round [rush / bull (3/4AP) + crushing hand (4ap?)] which adds to the carnage.
In comparison, barring a badly placed ice elemental of my own dying, I think I was tripped / knocked down once during my entire play through. I wouldn't want the ice elemental to lose ice wall, but I would like to see certain enemies immune to freeze and the other summons have comparable utility. e.g. there's really no point to the witches' summon warrior spell.
TL;DR
At the moment, knock-down / freeze / petrify [many weapons have 10% chance on hit] are the mainstay of any fight. I suspect that once mobs start using AP / skills correctly this will change, and probably slaughter players.