I would imagine that if every class had the same metacurrency that refreshed in the same exact way for the exact same amount, it would put off an equal amount of people than it is doing right now currently. There's no way for any company to win this design battle. Either method will irritate the same number of folks.
Most games with metacurrency have multiple... Then again, XP/AP are metacurrency, even tho' most don't think of it as such. HP also are on the border of metacurrency, especially when defined as AD&D did.
2d20 has momentum (PC)/Threat(GM), and a third, which varies by setting, destiny/luck/etc...
Fate has 1 unified, and doesn't have XP in most flavors.
Cortex Plus has 1, Plot Points. MHRP has a different one for the GM, the Doom Pool.
D&D 5E has 1 (Inspiration - very limited use, but it is metacurrency)
WFRP 1e (Fate Points)
MSH/AMSH: Karma (it's not just for advancement.)
WEG Star Wars: Fate Points, and in 2e, Character Points (Not just for advancement)
FFG Star Wars: Destiny points and XP; all the other metacurrency-style elements are not durable, so whether threat/advantage & triumph/despair is a matter of definition.