Hi, my house has a lot of MWBCs and I've learned to embrace them.
Curious to know if MWBCs are prohibited when associated with dedicated circuits required under 2011 NEC.
Keep in mind you need a 2 pole, common trip breaker for MWBCs as of late.
On the one hand I think it's common to use an MWBC to a well pump/tank pump setup. That's a fine idea, you wouldn't want one pump to start while you're working on the other, anyway.
On the other hand it might not be the best idea for an attic furnace, where a dedicated circuit for the heater and a separate dedicated circuit for an outlet nearby is called for. If the heater is tripping the breaker, you might need a trouble light or power tool to fix it. There are probably much better examples of places where it wouldn't be smart.
Specifically I'm wondering about dishwasher and garbage disposal.