You are totally welcome to give us feedback and to talk to us about what you'd like to see more/less/changed/tweaked/what have you. Your feedback is an invaluable resource to the dev team.
I'm happy about this sudden outreach from the dev team. I will be more than happy to suggest some things 
- Ability to choose enemy faction in lobby
If we can pick the map and difficulty, why not the enemies? Maybe we feel like facing one, or avoid another. More power to the player, and such. Also, I think it allow us to itemize gear, if only just a little. I have a Spirit Resistance Belt that would be great to use for a Demon run, but its not worth it over a Range Defense Belt when 2/3 of the enemy factions have archers.
- Remove friendly player collision
This is just plain annoying. Its silly when the entire team is running forward together and 1-2 of them seem to slingshot slightly sideways or backwards because of this. I find myself letting people pass me to avoid this awkward mechanic. Hmph, making me be polite ...
. If it cant be removed, please implement an action button to push/shove an ally out of the way 
- Add more inventory room..
I personally like to horde collect items. Uniques, Ring(s) of <Insert Skill Name Here>, weapons with funny names/effects. I have reached a point of being unable loot more than 1 chest before needing to salvage to be able to buy another. If new items/armors/etc is in the works of being added, I don't think I'll have enough room to add to the collection 
I'm sure there is content planned to include more, I guess I just want to give voice to this and hopefully expedite the process . I like to customize my character, do my best to look unique and diverse. Kind of hard most of the times with only 2 other armor sets (not counting basic armor set).
- Allow player gear//skill tree inspection
Plenty of reasons to implement this. You can:
- See the stats and effects of a yet not owned item
- Compare/discuss class builds more effectively
- Tell that warrior to NOT use that Berserk weapon
- Show off your gear more
- Judge your fellow player

Ice Wall is cool! Gib!
I have no way to know, but I'm almost sure this is going to be a thing at some point. In case it isn't, please consider. Would make for an interesting end to a run, also give Elemental Resist Belts a reason to be used. I find the Dragon fights in SP to be one of the best things in the game. Being able to do it in MP would just be great 
Just my 2¢. I already find the MP very fun (much more than I anticipated, haven't finished SP yet), and I'm hoping player feedback/suggestions can make for some cool additions that make it all the better.