Crucible drops were actually much better pre-patch. Ever since I think all I've seen is one legendary engram (for a different class) and Suros Regime. And I play Crucible like 2 hrs a day
Legendary engrams in general are extremely stingy now. You'll get them only for either doing the Raid/Nightfall, or very rarely through drops/chests (I'm talking like a legendary for maybe every 6-7 hours of play). Don't buy into that "blues turning into purps" crap either. I've turned in maybe a little less than a hundred blues this past week or so and had ONE turn into a purple...and it was a Shadow Price...which I already have.
Tiger Strikes seem to be the best option to try and get them but those higher level strikes can be both annoying and time consuming based on which strike you get (that strike with the super colossus is so tedious) so it really depends.
I've gotten less than 6 purple engrams post patch. Like, that's only a couple more than the number of Exotic bounties I've been offered. Wtf. It's not like there's a tiny amount of legendaries either so I really don't get why Bungie is so stingy with them considering how sort of lax they are with Exotics. Luckily I don't really care that much since I just need a pair of raid gauntles to have a full set but it would be nice to have some more purple weapons, especially heavies and specials.