I really like the wallet mechanics in Armory, the lockbox feature seems to be made purely for holding funds you rarely touch, there's no real quick way (That I can see) to keep generating new addresses easily for day-to-day transactions.
Indeed -- lockboxes were intended for multi-party escrow and/or low-volume transactions such as long-term savings. They were what we did to get some kind of multisig released and usable, even if it doesn't have all the features we want. The new wallets will do exactly what you described, but it might be another two months before we can get something release-ready.
If you build your own tools on top of armoryd.py, you can have it load multiple watching-only wallets and build your own command to "getnextmultisig walletA walletB walletC" etc. It's not terribly difficult, but retrofitting multisig into the existing wallet interface seemed like a waste of time when it might be just as fast to redo the wallets with multisig built-in.