BC2 rush had objective damage, collapsible mcoms, C4 vehicles, long range attacking from tanks and rpgs and other explosives, more open (wider) maps in general with more cover and less visibility. you just had to be more spread and open to defend because the attackers had more options. it kind of tipped the scales towards attacking as a few good coordinated attackers could beat all but the best defenders.
That's what made it more fun. There was more than one way to get the job done. It was super important for defenders to push forward and occupy as much of the Attacker's avenues of approach as possible. In future games, you only had 1 way to take M-Coms and it was way easier to defend them without having to actively push the attackers back as much as before. I also remember turrets being amazing in that game. Accurate and powerful. It sort of brought a bit of counterbalance to the wide range of options the attackers had.