I like floaty, and this ^^ is a close definition. Although… Elephark’s definition is funny, it’s akin to Steve Albini on “warmth” in audio recording.
The weird thing is that I would think “less rim weight” also, but the original Peak was pretty much considered the definition of floaty and it has massive rim weight. That massive rim weight on the very outer rim on the old Peak is also balanced by a hefty dose of center weight (and both are dialed back on the Peak 2 - see “let’s cut a yoyo” youtube comparison of old Peak vs Peak 2 cross-section - which to me is less floaty). Also Elephark likes the Peak, so whether or not he likes “floaty” as a term, he likes a floaty yoyo 
So… it seems that it’s not just more/less rim weight that makes floaty-ness. Certainly, it’s gotta be weight placement but it’s also the density (total weight vs. total size of the yoyo).
To me, floaty describes a yoyo that can be played fast or slow and also plays lighter than you would expect given its density. As far as I can tell, this can be achieved by placing the weight in the middle of the rim and/or evenly distributing the weight (not the outer rim or the center of the yoyo), or by balancing rim weight with center weight (a la the old Peaks). An old school yoyo with IRG and big axle is a good starting point for floaty, basically. Also hybrid plastics like the Protostar and Northstar were pretty floaty.
Not floaty: lightweight, heavy, small, center weight, aggressive v shape with rim weight, solid on the string, only fast, only slow
Floaty: Describes a yoyo that is lighter in play than expected based on its weight alone. Medium weight and/or density, medium size or bigger, balanced weight distribution. Plays fast or slow. Boring on paper, but versatile in play and an everyday carry.
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