Hot House feel like Airwave playing dress-ups, rather than a unique character.
In contrast, Ironworks and Greasepit actually felt like different characters, although there was only 2 parts different between them. The bowser, sign and relocated arm in service station mode, as well as a distinctively different colour palette made Greaspit feel like a different character. Even just not painting the control tower stem would have made a noticeable difference.
Gok - your fan-mode is pretty great and a marked step above the effort Hasbro made for him.