It is my opinion that health bars could use a bit of tweaking. First and most importantly they should be underneath units, much like they are in almost every other game in existence with health bars, even many of your games, Blizzard. Namely Starcraft.

http://i110.photobucket.com/albums/n99/chuiu/oldbars.jpg

Two more improvements so they are less intrusive and easier to read are the removal of all the black bars in the health bar. This was bothersome in SC but that was then and this is now. Sliming them up a bit and making them a bit smaller would also free up room to see forces on the screen. This isn't really important for the player but since you're making this an esports game this will help greatly in making the game more clear in streams when health bars are shown.

So pretty much this is what I think they should look like, though this could use further tweaking like a thicker border:

http://i110.photobucket.com/albums/n99/chuiu/newbars.jpg

I hope someone sees this.

Thanks for the feedback. The blocks created with the black bars and the placement above the units is simply for quick and easy readability. Your mockup definitely slims them down but in a fast paced environment it would probably be near impossible to quickly see the data they're there to represent. Sometimes staring at these things in screenshots makes them stand out in weird ways that just doesn't come across when you're actually playing. You may even find that you appreciate the info you can glean from a split second look at easily readable bars in a stressful match.

Options available in-game for health bars:

Normal: Only show when holding Alt
Selected: Selected units only
Always: Show all unit status bars