First off, it's 8 teams not 6 (probably 9 within the next 2 years with Ottawa getting their team back).
Second, it's much more than just one less down and a bigger field. Receivers are allowed to all be moving in motion before the snap and get a running start to the line of scrimmage, there's 12 players on the field, on punt returns you have to give the return man 5 yards before he catches the ball, there has to be a certain amount of Canadians on the field, the field goal posts are on the endzone line, the defensive line has to be 1 yard off the LOS, and there's tons more.
But yes, I would love to see the CFL in a football game. Currently I can only do that by creating teams in APF, NCAA and I'm guessing Backbreaker as well (I don't bother trying to make CFL teams in Madden because their jersey creator is horrible).
The thing is a CFL game by itself just probably isn't worth it. I know there's a few American fans and the league is just starting to get better exposure in the US now with the NFL Network deal but right now I don't think that's good enough.