We own a 2013 35' Winnebago product, Ford V-10 gas power. Yes, going up inclines, some steeper than others, causes the transmission to downshift making engine revs go high. This in turn creates noise. Is it intrusive? In can be. We all have different levels of noise tolerance. We are used to the engine's peculiarities and are no longer bothered by the roaring. When the transmission is in fifth gear it is relatively quiet up front.
The 2016 Ford F53 chassis with the V-10 engine and six speed transmission is reported to be much quieter than those earlier (such as ours) with the five speed.
Diesels have advantages over gas powered models and visa versa. We have used our RV on average of about four to five months a year since it was new three years ago. We find the uncomfortable furniture to be far more the issue than the high revs of the engine going up hills.