I think the most plausible theory of the loot system has to do with another post I read about where they want you to explore the full game for example if you use scout rifle a lot you won't get scout rifles because you already use it but say you don't use snipers you'll get a lot of those because they want you to explore everything. The same would apply to strikes and crucible so if you play a lot of strikes and decide to play some crucible you'll get better drops in crucible to try to get you to play more crucible. Also makes sense why inexperienced crucible players would get good loot. Just my input