Knifers irritate me as well. But if I let someone close enough to knife me I need more practice. (I've been knifed allot in the short time I've been playing BF2142.)
BF2142 Screen name: Sfakianos
I could take it or leave it. And besides when I'm playing on a team with a few good squads no one gets the opportunity to knife.
I like the idea of ranking/unlocks.... BUT.... I would still leave the benefits of in squad only perks. The game play is so much more intense and organized with squads.
Also please consider a SP option with all weapons unlocked so we can practice. Thats one thing I don't like about BF2142 Vanilla. I get a Field Upgrade and I have no way to train with it unless I get an unlock for the item. Kind of pointless.