Why were these features removed

[Noporian]

It's kind of a problem for me because automation isn't really stable, and once it didn't let me put an engine in, so why can't we save platforms anymore?

[maffc]

It was an interim change to allow work on a revised solution.

[Killrob]

I'll probably put out a new youtube video tomorrow showing how they come back, like maffc says it was a temporary thing that allowed us to release an in-between version. Platforms and Models will be saved continuously with the next big update.

[Noporian]

I just lost 2hrs of progress thanks to this removal because the game keeps crashing.

[maffc]

As an interim workround, start a new model, set a platform layout, add a body, a saved engine and use any settings and save. should take about a min.
Then you can tweak and save as often as you see fit.

[Killrob]

I just lost 2hrs of progress thanks to this removal because the game keeps crashing.

I'd say that's better than having no new version to play at all for another 3-4 months?