No-one is being forced to adopt Forge yet. We are trying to share our plans ahead of time to help you prepare where that’s possible (and give us feedback like this). We know there are still hurdles in the way. We’re working on improving the public issues as a first step; sorry the channels for tracking feature requests feel so unsatisfactory thus far.
The State 0 to State 1 jump is supposed to be really low friction. State 1 to state 2 is a bigger jump, but I guess one way to tackle it is one module at a time. I’m sure there are ways we could look at easing the transition, but I’m not sure if easing the sandbox attributes are the way to go - alongside static assets, they are the whole point of the migration. The other approach, which I think can already be done today in many cases, would be to add the attributes to your own iframe before migration.
Thanks for all the feedback; please keep it coming.