Unleashed Engine was the best engine, nobody liked any form of the lost world engine, seriously

I think the Lost World engine had a lot of potential, parkouring seems right for Sonic. The only problem was that it was new at the time and since Lost World was mostly one big experiment for SEGA, of course it's not gonna be perfect at first. I feel like if they really took the time to tweak it, it could be really cool. Or maybe they could find a way to combine both engines and give us Sonic Unleashed grade speed with Lost World maneuverability. I think High Speed AND Parkour could work really great with enough tweaking. If anything, my biggest change that I think Lost World's engine could really benefit from is actually making the run button SLOW Sonic down so you don't have to hold it to make him run but you can press and/or hold it to make him slow down when you want to take your time with something.

I still say an updated Hedgehog Engine, worked with unleashed, colors, and generations, and it's my absolute favorite engine

But I do kinda hope they can find a way to bring the parkour back and improve upon it because I feel like it could work really well along side the high speed action.

Well, it looks like you kinda got what you hoped for.