If you don't mind me asking why Ranger? Best ranged single target dps?
Did your two wizards just use the encounter attacks and wand for most battles?
I went with ranger because I thought it would be the best ranged physical damage output, and I could take the bear companion for a extra tank, which helped a lot early on, but not so much now that my fighters and paladin are immortal. In fact, unless I babysit the bear by keeping him out of melee combat and just using him to increase my rangers accuracy, it's useless. It doesn't ever manage to hit the enemy, and it dies so fast that it's just a penalty for my rangers accuracy if I don't babysit it. :/ (Bear companion is also bugged, it may be all companions, but I'm not sure. They have both 'health' and 'endurance' if you hover over their portrait, but they never lose 'health'. It would be bad if they did though....)
Also, I stuck to a bow even though a lot of other people seemed to like guns a lot more? For me, that's mostly because I don't like guns being in the game anyway. XD
Before my wizards got to level 9 and their first tier spells became encounter based. Yes, I stuck to wands and their 'blast' encounter skills.
Now, my wizards actually do quite a lot of damage with their wands.
I say quite a lot, but I haven't used guns or 2-handed melee weapons, so I mean 9-12 when I say a lot. xD Though it is to multiple enemies around the target due to the talents I chose.
I think one of the things that needs to be done off the top is change how effective damage reduction is.
It's way too strong as it stands now. If you can play through path of the damned without a healer, it's way too easy.
If the enemies do any more damage than they do now, archers will 1-shot any of your squishy characters. So I think just toning back damage reduction would be a good step.
Other than that, as many have said, the enemy AI needs a lot of work. If you engage a enemy in melee range, they WILL NOT leave melee range. Even if your mage that's doing huge damage is only 1 step away and at 10 endurance. Because they are 'engaged' they will not move from that engagement range. This makes engagement attacks useless to the player. The only thing they are good for is so that you can 'tag' a enemy as 'engaged' or if you want to put it another way, 'taunted'.
Also, forgot to mention I never bothered to eat foods or drink potions. Not once have I used any food, or potions. Or even enchanted any gear!
When I first started the game up, and I saw the crafting in there. I thought: "wow, this is going to be AWESOME!" Then I got to actually playing and progressing, and all the gear I found was better than what I could craft. And the foods/potions were so minor/had such a short duration that they were useless.
If path of the damned was actually difficult, I might have used food/potions. But the item enchanting system will sadly always be useless, with but a few exceptions.