What matters most in speaker design?

A, C, and D

No enclosure is best.

Price point, veneer, review, ad campaign, scuttlebutt, endorsements, gimmicky technological storyline, designer's pedigree, country of origin, power handling capability, and envy factor. Not everyone will agree on the order of importance among these essential elements.

The sound.

Weight.
The weight of all audio components relative to their function i.e only compare an amp to amp. The heaviest or most massive is always the better one.
Note I think the amount of wood in a wood or wood composite speaker can only be compared with another fundamentally wood speaker. Those granite thud rock slab speakers are cheating they get disqualified. Same with the lead lined cheaters thats not game.
So think about it which is better a thick highly braced enclosure or a thin non reinforced speaker enclosure. My JM Lab Focal Electra 938s are made with the same drivers (per JM) as the Utopias of that vintage. The Utopias weigh 3X as much.
Consider the drivers . Do you want that skinny excuse for a magnet always ferrite BTW compared to Alnicos magnets that weigh 10 pounds for a 1 inch tweeter and 30 or more pounds for a 10 -12inch woofer. Which is better. The bigger magnet. It makes for a more powerful motor in the driver it's true.
Finally crossover Skimpy three wind inductor a few small caps or....
So in sum, size or mass counts. Sorry fellow man, most woman are kind and reassuring but when they are alone...the size of your.... bank account really does matter.

No enclosure is best, I agree with Muralman1. That means planars, or certain special designs such as those buy MBL.

Soundlab, Sanders Sound, Quad EletroStats, Analysis Audio, Magnepan, Emminent Tech, Soundlab, GalloAcoustics, lots of cool choices.

Then the drivers, then the crossover network.