It can be fun to put an alternate airliner into service, but unless it’s really big, really fast, or both, a lot of people wouldn’t notice much difference. That being said, the same can be said about a lot of things and it’s never stopped alternate history writers before.

I’ve even made a couple “formal” tiers:

Tier 1: Barely Noticeable

Planes like these (in this case the MD-XX and the An-218 “777ski”), are going to be barely noticeable to non-aviation afficiandos, however different they may be on the inside.

Tier 2: Standing Out A Bit

The dreaded propfan is one instance of these airplanes having one obvious standout in addition to their other more subtle features. Others include a distinct shape like the 747 fuselage or even a “four engines all in the back” like the VC-10/Il-62

Tier 3: Really Stand Out

These involve strange but technically plausible shapes like lifting bodies or circular hulls of various nature. Their mere appearance makes them stand-out. This ironically applies to delta wings and civilianized early jet bombers.

Tier 4: Exotics

These are the ones that ascend into pure science fiction.