I like the thought of using your existing city to produce goods (give way to goods buildings, yes please) and troops (Traz, anyone) from eras most of us left a long time ago. So, it might add some additional benefit to those still in the era in question, but surely mitigated by the many who are in later eras with more developed cities. For me, this would remove the biggest obstacle to making QI a true proper guild feature that people could properly enjoy, and also remove any issues with it being 2 weeks overlapping GbG, since we have all of it already.