So essentially they are breaking all the addons now so just in case in the future if engine changes break the addon, they are technically not at fault?
Let's be fair here, they want to avoid engine changes to break addons in the first place, at least that's the promise behind this. And addons that don't use undocumented features need some porting, I'd not call them broken per se. No doubt, it's sucky still... but at least they CAN be ported. The group handler plugin will be actually broken with no replacement, period.
That's not sound logic, because engine change always have a chance to break your project regardless? Which is why if u have a game that's going to be released you stick with one version to mitigate those risk factors?
That is very true, but I kinda feel like doing version freezes is not common practice at all. And even then it still creates problems. If I have an addon that breaks after r391 and Ashley fixes a bug in the engine in r392 that I ALSO really need fixed for my game... I can have one or the other, if I really really need both, the project dies right there.
None of this is ideal, I don't know what ideal would actually look like.