[oofbey]

Why improve when you can start over? Modern tools for pub sub and websockets are so much better. We don’t need to use XML any more. (For the love of god please let XML die.) The old code and implementations are more of a liability than an asset, especially if you want to take out major functionality. Unless interop with AOL instant messenger’s install base is a key feature or something. (Don’t know if AIM uses XMPP but the timing is about right and representative of what you’d get.)

[Zash]

Why start over when you can improve? You'll most likely end up with the second system effect, probably slowly rediscover all the valid reasons for the things you disliked, probably re-make all the mistakes.