One thing I never managed to aquire in year one were some of the neon-green and black ships with nacelles introduced in The Dark Below, and AFAIK none of those ships drop in the strike playlists anymore.

Your un-acquired ones are also hidden from view in the Ships Collection terminal in the tower.

...but they do still drop in level 28 PoE.

28 PoE isn't as bad as I remember. It's fast, gives a reasonable amount of XP for leveling stuff, and the random modifiers keep it from becoming too repetitive. (WHY DIDN'T BUNGIE PUT RANDOM MODIFIERS IN THE HEROIC PLAYLIST??? ARGH!)

Also, the rate at which legendaries drop on completion is ridiculous. And by ridiculous I mean awesome. Systems-wise, HoW was Destiny at it's finest.