As far as the 'safe play vs. reckless play' is concerned, I think safe play is more common. Tournaments are filled with players that have 'unbeatable' decks. Some because they are damage heavy, some because they are like a fortress of defensive cards. Most often they don't want to lose a single unit to achieve their victory. Anytime you can encourage players to do something that breaks the mold and do something outside of the ordinary you are on to something special. Whether it is awesome or bizarre and useless is usually up to the players.
However drawing a card for each piece of damage dealt seems like too much of a reward for losing. Maybe I'm looking at it the wrong way. Draw every other card makes sense to me, or every card with a hand limit makes sense. Just as long as your opponent doing 10 damage doesn't end up sucking for them way more than it did for you. That encourages turtling and might make the game take FOREVER. I see the dominant strategy for that type of gameplay being trying to eliminate your opponent's units while not doing any damage to them, while saving yours to try and finish them off all in one turn.
I just had an odd thought though. What if receiving 'damage' was the only way you could draw cards? It could make things, shall we say, interesting.
On field space being limited I like the idea. It forces the players to choose their favorite units. The problem is if you have one unit that is a juggernaut it might end up being over-used.
