I've only recently discovered the true capabilities of BF2 transport ships. The simple fact is that they are VERY strong gunships, and that it is perfectly viable to play one throughout an entire match. They're not great for bombing capital ships, but they can stand toe-to-toe with any fighter or interceptor (the major disadvantage, of course, being the transport's poor maneuverability and turning rate). The other thing to consider is that if your transport has a lot of troops on it and you're destroyed, that's a lot of points for your opponents. Still, spamming cluster missiles and/or proton torpedoes is winning.