Before this develops into a lengthy discussion about this, here's my take (because that always helps with (un)necessary discussion topics):So what you're saying is that the dev has been aware of the problem for ages, and yet still refuses to add in the simplest of features? All of that 'optimization' they were bragging about earlier (something you really should focus on after the game is feature complete and you're no longer adding new content), and they still can't add in this little thing?
That's kinda damning more so than anything else.
Whether or not I've paid for it is immaterial, as if I had paid for this on Steam I'd have immediately demanded a refund. At the end of the day, I don't pay for games I can't play; and the dev swapping engines mid-stream is not an exception to that.
It's not that big of a deal. For you it's a priority, for most people it's not. For the dev it's currently apparently not. Is it easy to implement? No idea, probably. But instead of blowing this minor detail (which it quite fairly is) into something it is not and demanding personal preferences, maybe just wait for things to change. The game is way too early in its development phase to get mad about missing features like that, imo.