It would be great to see Sena (more tall, if possible) playing in a Professional League... heh.
But I suppose the authors won't make it so long, they'll finish ES21 once the last high school tournament reaches its end...
Adding manga to the list:
You should also read Liar Game
The problem is that at this point of Eyeshield 21, Deimon can ONLY keep on winning. If they lose a match right now, the plot has to start over. Fans will lose interest in the series if so. That sort of kicks the surprises out of everything. Basically we already KNOW Deimon will keep on winning, otherwise it will lose fan base. That kinda make the plot a bit TOO simple. Oh well.