[a3n]

Call it a clone, refactor, rewrite, fork, whatever.

If it gets subsumed into Vim I'll use it without having to choose.

If it gets traction as a second thing, I'll try it.

If it's better than Vim I'll keep it.

Let them write, good luck, have fun, I'll try it if I hear from HN that it's good enough to use.

I don't think it violates "don't rewrite" because these aren't the Vim people. Vim itself won't "suffer" from the ill effects of a rewrite.