I personally always saw the enemy Haywire as a more difficult and "stronger" version of Mr. Bomb. However, in my opinion Haywire does not seem more challenging than his blue counterpart. Sure, he can run after being hit but even then once the player for example jumps over a small gap, Haywire cannot follow which is pretty boring as due to complex level design this and many occasions where Haywire cannot follow will happen a lot making Haywire not really diffrent from Mr. Bomb. So here are three ideas that would make Haywire a little bit more challenging:
Maybe a speed increase could work, but the other two look like they'd make some things impossible and make level design harder. Older levels may break especially because of the first idea. I'd support the idea that there would be a customisable speed. But I think in cases where they're meant to be hard, they work quite well as they are, and when they're meant to be easier on longer platforms or just not hellish levels they are. It works quite well in my opinion.
It wouldn鈥檛 make level design harder as they would be similar to captain snowball then, movement wise. And using them isn鈥檛 hard too, isn鈥檛 it. Besides it's the level creator鈥檚 responsibility to make their levels work with the latest version of the game, not necessarily only ours.
It isn't just incompatibility, it's the removal of a potentially vital feature. It's not the job of the level creator to predict the future of how the game might change and completely ruin a level.