Now this is a good intention, but you know what they say about those... It seems to be saying 'never mind all the past compatibility we have broken and the older code we are no longer msintaining - it will be different in future!' Which does not have a lot of credibility, since actions speak louder than words. It would be better to undo at least the more recent breakages (say, by continuing to actively support GTK2) rather than rush forward to yet another new rewrite cycle with the promise that this time things will be different. Who can say whether four years from now the developers will not have forgotten? Keeping compatibility is something you need to practise on a small scale from day to day, as the kernel developers do, not something you can simply declare to happen in the future while ignoring the present and recent past.