If Chopin's ''x'' published as ''y''

[chopianologue]

I think Heroique Polonaise op.53 would be a great etude! In that way, it would be one of my favourite etudes. Not a normal etude of course, it would be Grande Etude Heroique.
Heroique Polonaise has a lot of technical exercises like trills with weak fingers, extended arpeggios, hand and finger stability, trills and scales with 4th's etc.
This piece had been a technic improver for me.

Also op.25 no.5 could easily be a waltz.