Looks wise: Very nice, definately a cool idea
Practicality: looks a bit cumbersome for a M4, but heck I use a DMR length weapon for CQC
Fairness: What about it? That's perfectly fine IMO, if it ticks you off play a match against him and be sure to hunt em down.
Nyax: Throw on a slightly longer barrel, a drum mag, and a bipod and there ya go