As for other decks that made extensive use of Leeroy, Miracle Rogue was probably most affected by the cost increase. Leeroy + Shadowstep x2 costs 11 mana now, eliminating the combo (short of tryharding with Pint-Sized Summoner... I suppose). Considering that Loatheb and Sludge Belcher are so prevalent (and so good), pulling off lethal burst for Miracle Rogue was already getting tougher. On the bright side, perhaps we'll see some new rogue builds and maybe even a viable Miracle variant.
When it comes to Starving Buzzard, I don't agree with such a harsh change to that one card. Hunter was getting out of hand, but this doesn't seem like the right way to fix things. One of the biggest issues with buzzard allowing players to draw so many cards was the amount of cheap/free answers playable in the same turn from those newly-drawn cards. When you can Buzzard + Unleash and still be able to play another cheap beast or two and any number of Hunter's Marks on top of that, there's a problem. I think a more reasonable change would've been 4-mana Buzzard (with a slight stat increase) and 1-mana Hunter's Mark.