I'm rank 22 almost 23 with cryptarch, probably handed in 15-20 legendary and gotten 3 I can use for my class, 3-5 legendary/exotics total combined for warlock/Titan that I dismantled for upgrades to my gear. If I had to guess, 2-300 blues and maybe 3-5 legendary out of them. I'm level 29 and just finally got all legendary weapons, it was a hell of a grind