Actually, they make up for a lot of what they lack.
They play a one big man style of offense, and he is only 6'8", however, their four guards are 6'5", 6'5", 6'6", & 6'7".
They have the player that can beat anyone. The stretch they had today where they went on a 23-5 run or something like that, their 20 point run against Illinois yesterday, and the 25-6 run on Michigan on Friday. If they play like that, there is no one they can't beat.
Yes they only have 6 players, however the tourney isn't that Grueling. You only have to play 2 games a weekend, and it is obvious that they have the legs to keep up all game. I'm not saying they will win, but they have the ability to beat Kansas, Kentucky, Syracuse, etc, on any given day.