Welcome to the forums. There are plusses to having a two axle trailer, and unless it has been discontinued, the 22' is available with a rear kitchen. The 22 seems to have more room in it than the 2 foot extra length would indicate.
If the 20' coach is enough for you, and you are happy with it, there is nothing wrong with that size. A tire pressure monitoring system would be a good idea, single axle trailers are more critical as far as tires.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.