Why not, if that is not a problem it could be interesting
Well, one negative thing we can say about headshots is that with some weapons it's harder to get them (engi rifle) but generally raters don't play that class.
And also one could say that hits are important too.
But imho that formula looks good, as it gives you points for 3 things:
1. kills - you have to make many kills (this is the same as the old system)
2. headshots - you need to aim well, plus you don't get many heads if you just fragsteal, which is good. Adding hits too would be cool, but unluckily with adre bodyshots make half damage, I think headshots are the best thing if you want similar results in different servers (adre on/off, fast shooting on or off)
And also, the old xp system gave 5xp for a kill with hs (in some servers) which means hs counted even before.
3. kills/deaths - (maybe kills/(deaths+1), to avoid divisions by 0?) counts kills again, so they weight more than hs, but this time you also need to avoid dying too much.
All in all I think this can't be improved easily with the stats we have (and given that damage cannot be used), plus if you read the previous posts this would be only the 'light weapons' score, to this you add battle sense XP and other things.