Two terms you may want to refresh your memory on: second system syndrome and Chesterton's fence. I've never seen a rewrite come in remotely on time, and I've se

Two terms you may want to refresh your memory on: second system syndrome and Chesterton's fence. I've never seen a rewrite come in remotely on time, and I've seen quite a few fail altogether. Often what happens is, in trying to solve the problem again, the developers come to understand the original system, which already works. It becomes impossible to articulate tangible benefits for the rewrite and it gets shelved.