If there is a successor to Thimbleweed Park, I think it would be great if the Adventure would use some more modern technology. I still remember the time of Monkey Island 1+2 very well. Both games were technically a real progress at that time. They weren’t “retro”, they were groundbreaking. But I’m also aware that this has a lot to do with money and that progress doesn’t come from nothing.
I think the E3 2017 Trailer of “The Last Night” is very impressive. https://www.youtube.com/watch?v=pupdeq1MoVw Optically pixel art, but equipped with modern effects and very opulent. I’m not an expert, but I suspect that this is not really pixel art, but modern 3D graphics with pixel art as textures.
I don’t know if some effects can be integrated into a future Terrible Toybox Adventure, but I wish it could.