Glide-wrapper does not interact with Diablo per se, just between your operating system and your graphics card, so it is not against EULA/TOS of B.net nor is it against the rules of this site as far as I'm aware (yes, I tried to check and couldn't find anything against it), PM'ing a moderator will give a definitive answer however.
All it does is translating the glide interface messages of the ancient 3dfx graphic cards to a form modern cards can use, because 3dfx was bought by NVIDIA so there are no cards supporting glide directly any longer and OpenGL became the industry standard instead of glide - and Diablo 2 is piss poorly optimized for OpenGL.
If you would actually search instead of surmise, you would know this is not the first time this has come up on dfans or bnet forums.
Blizz has stated that they will look into the glide wrapper tech, but that for now it is against the eula.
By the way, d2 runs very well in glide, as the game was optimized for 3dfx cards.
If you're stating something you would be better off getting your facts right with all due the respect.
Blizzard has stated clearly, that while a 3dfx glide wrapper is not something they support, it does not alter or affect the game files in any way and is not against the EULA. It is just a driver emulator.
They have however stated that they can not guarantee that warden will not flag it as malicious and put a ban flag on you for it. However, I've used a wrapper to play Diablo 2 for around five years on b.net with no problems whatsoever.
However with the way it works I gravely doubt the fact it could be even detected by the warden, because all such a wrapper does is installing a file called glide.dll (or glide3x.dll) into your system directory or the directory of the game and then you change your graphics settings via the games own D2VidTest and it just happily and obediently passes on the graphics calls to the wrapper which then moves them onwards to your graphics card in a form it can understand. The wrapper does not hook into the game code nor does it modify anything that isn't already supplied with it.
It is the direct equivalent of plugging a 3dfx card into your system - maybe a bit less efficient than the 3dfx cards themselves but modern computers will compensate for the efficiency loss by having so much calculation power to begin with. Detection of a wrapper would basically require active scanning of your local hard drive (or your hardware) which would break almost any imaginable privacy law conceivable and result in a lawsuit against Blizzard that Blizzard could not win.
And the game was more than optimized, it was designed to run in Glide, because it was "the shit" at the time.
And while dfans has a stance against things illegal, this is merely but a tiniest driver emulator, which can be used with every old game optimized for Glide.