I'm... Seeing some technical problems here.
Namely, the "Surprise Attack" rule is broken. Very broken. It gives massive advantages to armies which prefer melee, while having the potential to wreck any army which relies on shooting.
Also, the "Free troop unit" thing is wildly imbalanced from army to army. There's two ways to read it: Either you get a single, stock troop unit with a single free special weapon, but can't take anything else at all, or you get a single troop choice that can take any upgrades or extra bodies it wants, except that it can only take one special weapon and no heavy weapons.
Either way, you're tilting the scales hugely one way or the other. Armies with good stock troops that already cost a lot will have a huge advantage with the first option, armies with big squad sizes will have a huge advantage with the second option. (Just doing the math, Space Marine squads pretty much cap out at 200 points, but Orks can get up to 350 points in a squad, and Guardsman can go all the way up to 600. And this is assuming you don't allow Transports.)
Meanwhile, at any cost gives huge rewards to armies with cheap, useful, fast troops. Since the table will be played lengthwise, footslogging squads like Ork Boys will be all but out of the game by the time they die, respawn, and come back. But, say, three Space Marine Bikers with a melta bomb, combi-grav on the sergeant, and gravgun on a biker, now that's only 93 points and it will be able to get back in the thick of things in just a turn or two.