The problem is that Destiny is designed for casual players. In basic PvP, giving out the best gear with the odds towards tilted towards whoever performs the best does NOT favor casual players. That's why Trials exists so that players who perform better get better loot when they go Flawless, or raiders who can form competent enough teams to clear challenge mode. Players who win more often in IB will also get to rank 5 faster. Safe to say that Bungie will not make the loot system for basic crucible favorable towards whoever does the best, and will instead keep it neutral like it is now.