A new wall element, that is EHOLE but that isn't electric, would make stuff that have fusion/fission in EHOLE way more better and satisfying, it is a simple idea but it should be implemented in Vanilla, and it is probably easy to implement in the game.
This has been suggested before, and for that exact reason. It's simple, but might not be a very useful thing to add, although I personally had a time recently where that would have been useful. Either way, the most likely way to add it would be to submit a pull request on the GitHub. I'm also interested in what jacob1 says about this.