UI stuff:
The UI is fairly alright, IF you pin everything. That's alright though I guess, making UI elements removable for people who for some reason don't want to see their cooldowns/health, sounds completely stupid to me in this type of game but eh.
It needs to show a lot more stuff though. It needs an experience bar for one, no way to know when you're about to level that I've seen. It needs to display mana costs on the skills, currently it displays how much mana you need if you don't have enough but it doesn't let you calculate costs for a combo without hovering the skills/knowing the class. I guess it's the same in dota but considering the UI is similar to HoN/more open to stuff(you can check heroes mana directly, you can see their items without selecting them etc), I feel this should be an option like it was in HoN. Simple blue numbers for the cost on the skills.
There should be a scoreboard, or it needs to be more obvious how you access it, I haven't found it, only pops at the end of the game. If it's intended you can't see your team stats during the game, it should at least show their items permanently on the pinned team portraits instead of having to press tab. It should also show your own stats all the time(if the portrait is pinned), last hits and kda. Maybe also the info about your stats that shows up when you hover with your attack dmg, armor, movespeed etc, make it its own UI element you can pin down if you want to see it or not. Team last hits could be nice too since gold is shared, it wouldn't show individual last hits if it's supposed to be hidden but you could see if your team is having issues laning or what.
The Kongor lane screen thing should show how many votes every lane is getting, so you can figure ahead of time which lane it's gonna go to before it spawns.
The cooldown/skill bar part should in my opinion be thiner(horizontaly), I feel the distance between the left skill and the right skill is too big which makes it harder to tell at a glance the state of all your cooldowns. Compress it a bit, remove some of the space between the skills, maybe scale it down a bit too.
Inventory management is a pain in the ass. You can't move items easily, which makes putting them in the right keybinding slot annoying as hell, it seems to work sometimes, but only if you have like a full inventory or something, I think it tries to reorganize it so the items fill up in the right order but I want to put item X on slot Y all the time for example, depending on the binding. The ordering is also "wrong", it seems to be 456123 from top left to bot right, when it should be 123456 like you'd expect, basically switch bottom and top rows. Selling items is extremely unituitive and I wasn't even sure you could until I randomly clicked on a lot of stuff. There need to be a more obvious icon for selling, potentially put it on the other side of the screen. You also can't get the courier to come and grab the item to sell it I believe(not 100% sure when I tested I was in base) and there's no sideshops obviously, so if you're full and want something else it's gonna be annoying unlike using dota/hon courier mechanics.
I'd like for tab to show skill cooldowns of your teammates instead of their items(which is already displayed on the top anyway). That or show the skill cooldowns on the top, either of these. Knowing when your teammates have ultimates and stuff is obviously very useful, and so is knowing when they have a stun, or if they have mana for it.
Think that's all for now.
Edit: Remembered something, the multitap skills. They need to be A LOT more obvious, and at the very least it should be in the description. I wasn't aware they existed until I saw someone throw 2 rockets in a row with what's his face and I was like "huh" then logged in vs bots and yep there it was, some weird ass little thing on top of the skill that seems to show it has charges. Turns out Minerva has charges on her blink strike too, which probably is one of the reason I had so much trouble with her. Oh and if I play in a 9bots game, I should be able to leave instantly, it sucks you have to finish the game.