I was thinking about end game content.... (Why are you thinking about end game content?! the alpha isn't even out yet!) yes, yes I know. But hear me out. My problem with classes is that it locks you into a set of moves and usually a role in a group. That is great and I totally understand that for game balance and team building. However, in the end game, I would like to see the ability to steal a power from another class/power-set. It could of course be scaled to whatever class earns it. It could also take a lot of grinding and time and resources to gain. You can't really call your character a beast at ice powers if there are some glaringly obvious things missing from his skill set. For example, a ranged ice based character might want that fancy ice shield that the tanker class has. It could be scaled to the ranged class so that it doesn't cause balance issues but I still get all the sweet ice powers a proper ice hero should have. Just some thoughts.

Why wait for end-game in the first place?

A diverse set of tertiaries that can take effectively any look that is suitable, on an individual power basis, should be more than enough to fill in those gaps. From my understanding VO won't be that rigid in the looks of powers, and one example I have heard of (not sure about exact validity) is being able to make fire powers look as if they are ice one, setting up a frostburn or frostfire theme.

I agree completely. I was just going off what I have seen of Valiance, which seems to have a similar setup to the old super hero city games. If I understand correctly, there is a primary power set and a secondary set. I imagine at particular levels you could pick one from either of those. But I would like to see at least some "pool power sets" that can be used to round a character out. Maybe they are full sets you get access to at a particular level or maybe they are small sets with a particular focus. Just brainstorming here.

they will likely have paragon powers added at some poitn also or something similar, city of heroes had primary and secondary power pools then a number of optional auxiliary power pools(speed flight teleport leadership ect) and paragon power pool after you did quests for it at max lvl, paragon power pool had things like a hold or a ranged snipe depending on what paragon path.
they seem to be doing a similar setup for valiance with added IO proliferation as blacke' mentioned(they said in a live stream one io would freeze opponents like it was ice but you could attach it to any power) so you have like 50 different special IO effects along with + damage - energy + acc + range + recharge extra enhancements