It's still more painfull than leveling an xbow, a 2h or a 1h. Dunno about cavs though.
You can have a steady 15/15 at level 21, with max WM and PD, and a bit of athletics or whatever.
You'll still be squishy, slow, useless in melee, inaccurate.
It's way more fun leveling a 2h, if your blocking skills are up to it. You're already competitive and a force to be recon with.
Also, no matter your awareness, if you don't have teammates, you'll get picked off by cavs or sprint shielders pretty easily.
I usually play on siege at low levels. Though people tend to have higher tier armor, and there's less horses.