I know its just a game, so I guess your asking when does it stop being fun?
Well I'd have to say it stops being fun for me when I dont even have a chance to land. Even when I was new, there was a chance I could make it back to base after a battle. Lately, I seem to encounter lopsided numbers, with alted uber rides. The alted uber rides will run ya down and let the TnB guys finish.
I'd say its ok to take a few advantages, but ya gotta ask when is enough?
If you have a large numbers advantage combined with a truce with the other largest numbers side, do you really need to have 20k spitfires and the like to pick on the country with the fewest numbers?
I dunno why ENY wasnt in effect last night, maybe it was & the la7s, spixteens & N1ks I saw were just re-arming and never getting shot because they had 7-8 others clearing their 6 if anyone dared to fight their 25 player horde.