once you think that security is no problem, it becomes a problem.
He is not asking about security.
It is not a good idea. Each time you do a transaction the wallet uses or creates new addresses and keys for the change. If you go ahead you would have to sync both wallets before you use them and besides, you could not use them at the same time.
This is with the bitcoinqt, don't know if the sames applies to armory.