@geraltitude: entirely up to Capcom. I'm going to guess no. Right now the only PS4 games that support PS3 sticks are Skullgirls and MKX. If Capcom doesn't support this, expect everyone afterwards to follow suit.
@yokelbloke: that's accurate and you don't have to burn your free 90 right away. if you get your old toon up to 60 (and buy WoD), you get 600 skill in your two selected profs. You also can opt to make that 90 on any server.
You can really quickly report someone who is AFK. Personally, I think it should be even faster. There's also no good way to punish people who leave matchmade games early (like WoW does). I'm also not certain what if anything happens to the people you report. Unlike DotA and WoW, Destiny doesn't tell you if any action against someone you reported was taken.
If you've ever played WoW, 20 is simply the cap that experience can grant you. Light levels granted exclusively by Rare, Legendary, and Exotic ARMOR (not weapons cause you'd be switching them out too often) are further powering up your abilities without 'actually' increasing your level. Like how in WoW, you have your level and then your item level. I think people will be surprised when a Destiny expansion comes out and Light fades from all their gear. That seems super likely. Light levels DO enhance your core skills though in a substantial way. Like, a 26 would get creamed in a 28 strike, but a 27 might actually do okay. It's that profound of a jump.
I can't help but feel like this game is the first third of a quality MMO experience. The reason why WoW was an overwhelming success was because those first 60 levels of content were just crammed with memorable diverse experiences and people who were playing just to cap had a lot to do on their long journey there. People who were just in it for the loot also found an immensely challenging and equally rewarding experience in Raid content. The obvious comeback is "well, WoW is a subscription based game.", and the immediate response is Destiny is asking roughly 90 bucks for all its content. That, at launch, would have bought you the game and roughly 4 months of game time.