When a cab is mic'd, the sound engineer still has access to all of the same knobs and buttons that he'd use to scoop your sound when you go direct, if he so desires. I'd say that in practice mic'ing changes pretty much nothing when it comes to sound engineers doing things to your sound that you disapprove of. Just saying.
I will add this though: I feel more confident that an engineer that is interested in mic'ing bass is less likely to treat bass as an afterthought. That has nothing to do with tone from mic'ing, it just displays their interest in bass.
Tons of engineers that prefer bass DI'd are also just as bass-friendly, so I don't want that to come across the wrong way, but if an engineer takes the time to mic up a bass cab, you typically know he means business.
