(B-) --> B
It needs more love than B- to evolve.
I Think sylveon have gotten far better with the ORAS metagame, mostly because hyper offence have gotten worse, it is able to shine through on the playstyle, that is now also arguably the best, balance. Sylveoff have two viable sets, specs and cleric (although cm is also a thing, but very comparable to specs in some ways) it have great mixed bulk, high hp and actually really nice offensive stats too. It is in many ways comparable to clefable, or at least cleric clefable. Sylveon lacks a bit of physical bulk, but fable needs almost maximal investment for this to apply, and on the other hand sylveon have base 130 Spd compared to fables 90 I think this is pretty much made out for. Sylveon also laks rocks, but considering you would already try to fit wish pass and heal bell, sylveon would not have space for rocks anyhow. Sylveon also hits ~35% harder than clef.
It also have the amazing specs set, which does a really good job breaking the checks of its cleric set, such as skarmory and heatran who would get in hoping to get up rocks, just to see themselves getting 2hko'ed by hyper voice and HO ground respectively. It's specs set serves really well on balance like its cleric sister, but is also really amazing on volt turn, where is can act as a strong special wallbreaker, or even give momentum with baton pass.
To put it into perspective, a choice specs sylveon hit harder, with hypervoice than even the special wall breaker mega gardevoir. It's power even comes close to that of mega zard Y.
252+ SpA Choice Specs Pixilate Sylveon Hyper Voice vs. 252 HP / 0 SpD Mega Mewtwo Y: 238-282 (57.2 - 67.7%) -- guaranteed 2HKO
252 SpA Mega Charizard Y Fire Blast vs. 252 HP / 0 SpD Mega Mewtwo Y in Sun: 268-316 (64.4 - 75.9%) -- guaranteed 2HKO
A lot of new mega evolutions in ORAS also lets sylveon spam hypervoice with even more freedom, as it now checks a lot more of the top tier threats! Sylveon have also, unfortunately, gotten some new counters such as mega meta, but checks to these threats can be fit onto most balanced teams, which is already sylveons favorite playstyle.