super mario maker, levelhead [1/3]
I think that the biggest problem with super mario maker is that level editors like this encourage you to make tricky stuff, but the time penalty for dying is far too large and frustrating!
You can see this with basically everyone who plays mario maker levels - every time they die, they immediately pause the game, go down, and select "start over", because even though that takes several seconds, it's still faster than waiting for the death animation.
super mario maker, levelhead [2/3]
And it's something that Levelhead almost got right - restarting from death takes a fraction of a second, so you're not waiting around to restart much.
But I think it might also be too short - which encourages people to make even harder levels, often artificially hard to the point of requiring random chance to beat. Even the campaign's levels are incredibly hard, and the user levels are even harder, which ends up with the game being innaccessible!
super mario maker, levelhead [3/3]
what I think would be best is levelhead's gameplay mixed with mario maker's levels:
You get the speed and interesting mechanics from levelhead (like the different costumes, the box delivery mechanic, bonus coins actually being interesting), but without the elements that make levelhead obnoxious (the difficult enemies, the visually unclear rotating cannons and sawblades, the bullets that move too fast to predict.)