I would, but the leveling system sucks, people always have an advantage over us people, my ping is a bit to high to dominate as much as I should, and I hate servers that ban Grenade launcher, and assorted perks. I hate getting Marytr'd but I live with it. I HATE steady aim, because aiming down a sight should be nearly a requirement for getting a kill.
This is an illusion. They just have more practice. I dont have any savegames left and could easily kill and level up in huge steps with beginner weapons. Just depends on how you use them. (and no, I dont like playing on noob or mass Servers)
Some of the unlockable weapons have a faster rate of fire than the big 50 cal machine gun I like to use, rendering it pretty much impossible to beat them using my lovely machinge gun.