I really hope that they let the RBN work in places like Australia if they bring it back. It wasn't fair that I couldn't get any of those songs cause there was so many good ones. Don't you want my money!?
Blame the RIAA and its Australian equivalent, that's all copyright issues, not just Harmonix deciding not to release it there. They had the same issue with Rock Band Japan and their insane music industry.
It's unclear what will happen with the DLC under expired licenses (e.g. Metallica) but it's assumed that they won't transfer unless/until Harmonix is able to reacquire those licenses.
You'll be able to download anything you bought from the store, you just won't be able to buy it for RB4 (or RB1/2/3, for that matter)
So you'll be able to get the Metallica stuff just like you can now, and Red Hot Chili Peppers' Blood Sugar Sex Magik, etc. The only thing you're going to lose are the things you can't download now, anyway.
The amount of manual labor involved in getting the songs into the system for the current gen consoles from the previous gen is such that there's no way they're going to spend the effort to go in and down mix the keyboard stems into the backing track, or really do anything to the actual files themselves. (Something like 6 months of someone working 40 hour weeks doing NOTHING else, and never screwing up, just to get one platform done.) So in all likelihood the midi data for the keys charts, and the keys stems, and the pro guitar/bass for the ones that have it, will all be in the actual files, just waiting for Harmonix to update the game engine to parse the data out.
Also, a lot of people don't seem to realize this, but harmonies are not
guaranteed to be in RB4, they haven't actually announced that. It's likely
, since the amount of work involved is not much compared to keys/pro guitar/pro bass, but very, very few people actually used the harmonies. (Since not many people bought RB3 compared to the prior ones) It's down there with the "character creator" in terms of priority.
However, they are designing the game to be much more modular, so that they can add pieces (e.g., sell you them) later. So it's possible they can add keys back in as a paid/free upgrade, or harmonies, or new gear for characters if you have them, etc. (There's no reason to not add a character creator store that allows you to buy more dumb crap for your in game avatars, that's how Valve and Relic make hell of money.)
I'm going to have to get an XBONE because all my DLC was on the 360, and MS should be paying Harmonix a bounty, considering how often I heard the same story at PAX about people who'd gone from 360 -> PS4, but I'm definitely keeping my 360 around to play custom stuff, even if it's JUST custom stuff. Also, I basically play Pro Drums and Pro Keys, so I'm gonna have to keep the old system around to get my Keys fix.
And I wouldn't be terribly surprised if, when they start releasing RB4 DLC, it's all released for RB3 as well. After all, why not? They won't have new instruments or something that RB3 won't have. So, why NOT release the songs for the older audience? If the QA cost is marginal, then it won't take much in sales on the RB3 stores to justify the release, even "hundreds" of sales should be sufficient to justify a few hours of old gen QA to make sure the songs don't break on PS3/360 (Wii is probably hosed) That's just speculation, though.