I'm almost positive that the way it works is the glyph leaves a 10% snare on mind flay today on live (the glyph didn't change in 3.2). The reason is because we thought it might cause a lot of bugs related to whether a target was officially snared or not. A 10% snare isn't particularly useful but it is noticable.It's simply confirmation of what was hinted at in the class Q&A.
What we're talking about is changing the glyph to not affect the default snare at all. The glyph would just boost range.
So Blizzard is now happy for us to glyph to extend the range of a spell which they previously thought would be overpowered at 30 yards. Yet they apparently think it would still be overpowered with a baseline increase because they continue to refuse to even entertain that option. I don't get it. I mean, it's not like we're loosing dps by glyphing for the range - because WE HAVE NO OTHER DECENT GLYPHS.
Will someone please remind me why mind flay has a 20-yard range because I've been temporarily rendered braindead by the shaman shock boost to 25 yards.
Edit: changed confirmed in the patch notes for 3.2.2, released today: "glyph of mind flay: this glyph no longer reduces the magnitude of the movement reduction on the mind flay victim." Which, in English, means the glyph no longer reduces the snare. Blizz, if you're reading, I'm available for translation services, very reasonable hourly rates...