Not related to this at all, but I've never liked Sphinxes as blue's iconic creature. This card's type is an act of reluctant conformance.

What's wrong with Sphinx? What's your idea of iconic blue creature?

I think it's just a personal hatred. For some reason, I find sphinxes feeling forced in a lot of settings. I don't know why, as none of the other iconics particularly bother me. Thinking on it, all planes sphinxes show up are fine with me. Maybe I think there are too many sphinxes having appeared in such a short time. I guess I just don't like sphinxes for some reason.

I like djinn, leviathan, and even kraken all more than sphinx. Djinn I would say are about as restricted flavor=feelwise as sphinx should be, and djinn are the only other ones that feel innately flying (though a few leviathans have flying, it's not a consistent feature of theirs). Honestly, I'd rather have monstrously-sized birds over sphinx.

Yet weirdly I have no problem with manticore.

Hmmm - yes, I guess there's only so many places you can fit sphinxes in and fit the theme. Although their existing both in Grecian myth and Egyptian myth does help somewhat there.

Trying to suggest a localised alternaive for this set - it's theme is... Unclear. Italian maybe? I'd say we've not had a megic setting picking up on that part of the mediteranian yet; but we've had "Guild city with carnivals" which probably is the serial numbers having been filed off.

I wouldn't have an issue with this being a roc - some kind of bird of omens maybe?

Fiora is Renaissance Italy, although it hasn't appeared in a premier set

The setting is set in what is primarily intended to be an analogue of Italy. My main inspiration was a memory of a scene from the Count of Monte Cristo and what I remember of the Italy pavillion at Epcot. There's a reason I said arts and carnivale and not Italy in my description. That is to say, the arts in general are the basis and not whether or not those arts appear in Italian culture.

Mercadia resembles Renaissance / Medieval era Europe / Persia.

Your issue may be Sphinx in our present-day world mythos is almost extinct, thus hard to relate or feel attachment. MTG is the rare major fantasy creator to revive Sphinx into pop culture. Although it seems not to wild success. Definitely no comparison to Angel dragon demon. At least Hydra has a unique mechanic. Yet Sphinx feels like any other generic flyer.

Speaking of which is the over representation of flying among iconic types. Such that blue being a primary color for flying becomes moot and less special. If red and black icons didn't get flying, then Sphinx would stand out a lot more.