I have to agree that whatever elusive quality it is that answers the question "Why should I play this
hack?" is what I look for when I decide which hacks on SMWC I want to play. Presentation is as good a term for it as any, I suppose. For this reason, there are really only maybe a dozen hacks I've played that I find actually memorable.
At the basest level, seeing screenshots that I find aesthetically pleasing is often what will initially draw me into playing a hack. For me, a hack needs to at least look "pretty" (or at least interesting) to get my attention most of the time. Level design is important, sure, but I'm not going to play a hack with great level design if my eyes are being assaulted by ugly graphics or horrendous palettes. Conversely, though, lots of hacks look great but play like crap, so appearance isn't everything. The hacks that I've enjoyed that had great graphics went above and beyond that alone and had a unifying visual aesthetic wherein every level looked like it belonged within the same game. (In other words, levels didn't see-saw between using Kirby Super Star graphics and YI graphics and SMAS graphics, at least not ones that clashed.)
Beyond visual aesthetics, I really appreciate any projects that try to do anything interesting and outside of the norm. Arnpoly's SMW Competition Cartridge is one that comes to mind, wherein he attempted to duplicate the experience of playing the in-store contest cartridges that were made for certain SNES ROMs. Anything Sonikku does with the SMW engine tends to be interesting, from making it essentially run SMB2 to his Blooper-themed hack where you roam from puddle to puddle to survive. It's great to see people making this old game have new flavor. This is why, despite its faults, a hack like Brutal Mario stands out from several arguably better complete though less ambitious ROM hacks.
[?] Miscellaneous Helpful Hints
If I moderated your hack, there was apparently a 90 percent chance it was rejected.