For the purposes of this post, assume a 10 minute timer, but also define a time-out as going over 8 minutes, not 10 (meaning that the increase in timer caused more campy play and wasted tournament time).
Because the difference between 8 and 10 minutes is 2 minutes, or 20% of a 10 minute timer, a 10 minute timer would save time if it deterred at least 20% of timeouts that would have occurred under an 8 minute timer. As in, 20% of games would actually be played less campy.
One side says that those who play to time out will play as campy as possible, which means that 0% of games would be played less campy, so if they're right, the timer should still be 8 minutes.
The other side says that people only start camping to time out when they notice that the timer is running low, which will happen much more infrequently during a 10 minute timer match, meaning that not only does the timer not reach 10, but it doesn't reach 8 because there is less stalling than under an 8 minute timer.
So it comes down to, do you think people stall because they can and because they go into the match knowing they will stall, or do they make the conscious decision to change playstyles once they notice the timer getting low? Do you think 20% of games will actually discourage the stalling that would've happened?
(I think statistical analysis would make a lot of sense here.... do any numbers on the matter exist, or are they on the way?)
EDIT: I guess what I really mean is that M2K's argument must refer to timeouts as matches going over 8 minutes, not time outs under a 10 minute clock. If 10 minute clocks are used but every match is 9 minutes long, it's technically not a timeout but the tournament is slower, people played campier, etc. (And the 20% bit, if that's even logically sound.)