Certainly no melodeon would be complete without bellows... but what qualities make a set of bellows extra special? Mostly, while I'm playing, if the bellows are doing anything that makes me take notice of them at all -- creaking, sticking, wobbling, then something is wrong.
The bellows of my Mélodie were made by the family of the builder. The components -- made in Italy -- are readily available from several suppliers, and the cloth that creates a decorate appearance appears to be something that was picked up at a fabric store. It is also possible to use paper -- witness the excellent bellows that are installed on Castagnaris.
The bellows on the Mélodie open and close with ease, and are of course airtight. What more could I ask for?
Is there such a thing as 'bad' bellows? You bet -- I've tried some cheaply made boxes that had bellows that were so stiff that playing the instrument was a chore, resulting in a sore wrist.
Is the player's use of the bellows comparable to a fiddler's bowing? In some ways. On a one-row accordion, one does not have a choice between pressing and drawing the bellows for a given note. However, on a multi-row box, the choice between playing across the rows and maintaining the bellows direction versus reversing bellows direction does affect the articulation of the notes in a manner somewhat similar to bowing.