I don't see why people are having trouble with the randomness. I, personally, think it's an interesting feature. It isn't the cards you get. Its what you do with them.
"I think he's over here" "Not a chance!" "No, really. I think he's back there." "Rookie, get over there and check that far off open area" "But I'm positive he's over here" "Damn it Rookie, do your job!"
Where does it say that the person controlling the pieces is playing Tetris? This is an avalanche of tetrominoes, 4 block pieces. That's why it's called TETRis
It starts out that way, but then opponent mages start being able to match your excess. First four rounds always run the same way (10 att v 10 def, 10 def v 10 att, 15 att v 15 def, 15 def v 15 att)