So far playing this game (and it has run fairly well on my machine) the groundwork definitely seems to be in place for a great game. All the staples of DotA are there, and I'm sure we will see how this game has improved upon that foundation as the Beta progresses.
However, my biggest concern even immediately upon starting to play was that everything seems far too small. One of the biggest strenghts of DotA is that everything is large and unit profiles are easily discernable from one another, which makes micromanagement easier and makes it easier to tell what's going on.
I understand that there's a zoom feature, but even when I zoom in all of the soldiers (minotaurs for example) are tiny. The towers are pretty small in comparison to the heroes, and the heroes aren't that easy to pick out from a pack (besides the Rook). I'm not sure how to specifically deal with this problem but I think the first step would be to make the "creeps," that is, the minotaur soldiers and what have you, significantly larger, as well as all of the buildings on the map.
I shouldn't have to zoom in to see the details of something close to me and then zoom out to move around to another part of the map. It's really important that everything be really clear to the player just by looking at what is happening, that way the player can focus on strategy and fighting instead of squinting to see what's going on.
Heroes should probably be a fair bit bigger, as well. The Rook can probably stand to only get a little bit bigger, since he's decent sized already, but looking at somebody like Regulus...well...he's tiny. At the very least heroes need to have a sort of glow around them or at their feet so they are easily distinguishable from other units.
That's how it is in DotA, and it works really well. The main reason why everything is so large in DotA is because it's a mod of WC3, a game where everything is designed to be really big and immediately recognizable because it's a game that is centered heavily on single unit micromanagement. If this game is to be successful, it needs to facilitate that as well.