After getting the game I though about it....
I live in the uk. People in USA had the game about 1 day before me... In that time some people had reached lvl 23, out of 35 lvls.
Although there is a serious advantage to be gainned by being a higher lvl, low lvls can still kill higher lvls, (though head shots, or shooting them loads)
I'm not sure what to make of it yet... With games like halo 2 turnning people evil in the atemped to get higher ranks, (by evil I mean cheating/cheap play) what would having a lvl system do for a game?!
check out planetside
http://www.gamespot.com/pc/action/planetside/index.html
http://planetside.station.sony.com/screenshots.jsp
its basically a FPS mmo
and no its not a new idea to have rpg elements in a first person..
Deus Ex was one of the first to bring that aspect into the genre