OK, lets put you and 5 random ET noobies on one team, and 6 CAL-I (or whatever the euro equivalent is) RTCW players on the other team. Now lets see how much ‘determination’ helps you get out of your spawn, let alone win the map.
Shuffle is by no means perfect. I usually vote no if the teams are not hugely unbalanced, because it can certainly make things worse. This is especially true on servers with long campaigns, where XP is more of a measure of how many hours you have been there than skill.
There are a certain number of people who call shuffle every time they lose. Obviously, that is silly. OTOH, if one team is completely pinned in spawn for the first 10 minutes of a map, that is a good sign that shuffle couldn’t hurt.