Love the freeze/glue grenade ideas.
Like a frag, they can be avoided and both wouldn't deal any or much damage, presumably. They sound like great additions to me.
I would imagine a freezing grenade would freeze enemies directly hit for about a second then leave the surrounding area covered in ice so movement would be quick, slipping and sliding.
A glue grenade maybe just leaves glue around the surrounding area so no one can slide and movement is slower over that area for ... 10 seconds or so?