Well all fights I remember from DOS1 were like this:
1. KNOCKDOWN EVERYTHING
2. Stun what you missed
3. AOE those lil shits down.
Those stunlocks were too real to be honest....
In dos2 i feel like my starting positioning and target priorities are now more important, which makes it fun for me. I also have to implement different tactics for dealing with enemies... And of course, when some meele rushes your mage, it isn´t mages job to 1v1 him, he should gtfo, let warrior take care of it, and then spam support/aoe spells on proper enemies.
Also diversify your party - I have polyscoundrel with me, and it had troubles when there were strugglers with low magic armor, but high physical - it helped immensely to just add one point to aero, one to geo, and pick fossil strike+electric discharge+shocking touch. It has cost me basically nothing, I dont even use int, he is just all finesse, but it has great effect, as he can now finish of stragglers, have ranged attack and can combo with my mage for stun. Do this for everyone, and you are good to go (rangers are great with geo+pyro!)