What if you took a bike that was SLIGHTLY too small for you but then adjusted the seat to a high setting and raised the handlebars as much as possible (maybe even a little more with a stem riser). How differently would it feel or handle compared to a bike that fit you better?

FWIW, this is a somewhat inexpensive bike that'll be used as a back-up bike for occasional rides . . . my "B" bike if you will