That's the whole point of having 3 teams. Avoid unilateral victory. Frontlines is not about being the best at pvp, it's about having a strategy depending of how good your team is. And if a team is clearly better, having the other two team up for a time is the best way to try to win. That's why (nearly) every pre-wow pvp oriented mmo had a three faction system. Most people don't seem to understand that, seeing how people don't even look at their map for node spawns.

That said, in frontline, it often end with people fighting for the second place. So I don't really see where that complain come from.