i just play it through the third time, almost done.
Started with warrior which is quite challenging, but i also prefer enemys doing more damage instead of tons of HP and long boring fights.
On the other hand my second play through on adventurer difficulty was quite relaxing. After a few quests i had tons of gold and could afford even spells that i didnt really need. Sure its fun to have enough gold, you can experiment and try out different stuff but i am not sure if thats really fun for 4 chapters.
On warrior my equipment broke every fight, after the patch with adventurer it was much less. 2 days ago i started the third run on adventurer - mainly because i wanted to test other classes and spell lines this time, so i took easy mode and well my weapons broke approximatly 3 times in a few hours - thats almost boring. It should be somewhere in the middle, you should be forced to repair but not every 30mins. I think a second (or even third) set of weapons should be a must.

Mobs can be killed in adventurer just by clicking fast the 4 attack buttons, which is also very boring. No real challenge.
The mobs shoulod really do more damage and there should be some option (i am not sure what the "shield" - defend in a fight really does) to really be more protected for one round, for example if you want to let the regeneration spell healo for a round, you should be able to really defend yourself and have a high chance not to be hit. Was that clear?
On the other hand, what a other player pointed out, the taunt spells are nice but they are really too many heavy. I use it 1-2 times on a melee and the mana is gone. In easy fights i dont care but if there is really some challenge, the spells should cost less mana. I am not willing to train/learn to have more mana on my defender/merc etc.
The tanks would be more useful with that. Right now i dont really see a reason to even take a defender (at least in chapter 1 and the 2 available diff. grades)
Merc and Barbarian both deal way more damage than the Defender. Ok i have to sell all shields i find, thats a pitty, but hey i do much more damage.

Now the spells. Well i had in all 3 runs a caster with regeneration. Using a heal potion in combat is for a melee only the last option.
I think some spells are way too mana heavy. Ok its great to freeze a few enemys but 30 mana for just 1 round, oh well. I think that lots of spells could really work for a longer time. Some spell durations have been teaked i think.
I love for example the buffs, like the prime spell that raises crits for a few rounds, this one last a whole battle, thats really great.
My last run was with just 1 freemage, well that works too kinda, not sure how it would have been on warrior level.

The npcs that join the group do nothing right now, but i guess you know that :P

In the first run on warrior i didnt find that great gear and had low money, the second run on adventurer was much better and at the end of the second and in the third run i suddenly found really good blue items. Was for me like the developers are thanking me for playing so often :P 'Well thats a really nice feeling if you find cool gear. Especially if the best items you find are mostly green color and raise just 1 stat - most weapons have +2 damage

Ok thats my feedback - i am not sure if anyone read it till the end, i am from austria, so my english is not perfect.

Have a nice time
Keep up the good work developers