petty rule imo...if people are camping rooftops and you cant get up there/shoot them, get out of their line of sight. Make it so they can't engage you from the roof, while focusing on the rest of their team. If they are the last ones left and you have no ranged to shoot them, just sit back and wait for the flags; thats why they were put into the game.
A lot of the complaining I see seems to boil down to Inf wanting to just walk forward until they or the enemy are dead, without having to deal with cav or archers. Be accountable where you are and aren't walking. It's not like there are a lack buildings to hide behind for cover on any of the maps except for the rare random plains sighting.
Also for the "your wasting my time" argument...I don't buy it, we're playing computer games and posting about it on the forums...that extra min waiting for flags to spawn doesn't amount to much.