I can see them spanning out the weapons to swords (glaives being part of swords), fist weapons, axes, and polearms (maybe staves).
Why the 2-handers?
If I am not mistaken, in the Visual Guide just released they make the comment that Illidan's blades can be used as two single handed weapons, or as a two handed weapon. We already have polearms referred to as a glaive:
http://www.wowhead.com/item=47239
You could also allow DH's to "break" magic weapons and infuse their glaives (a special class only ability like DKs runeforging), while releasing a single new glaive design (graphic) once a tier or something.