I never thought they'd go back on the Portal but looking at how they're already changing core mechanics in it - such as modifiers not adding power to enemies - I could see there being some big changes in the future. I think it will remain a hub for activities though. The real issue is that old content was abandoned - rendering it completely moot. There'd be less bickering if we could play old stuff and get updated gear - or even work on our power levels that way. And I think Bungie would have wanted that too but just doesnt have the resources to make it happen atm. They also need to make the vendors relevant again.