I like a lot of these ideas. Nerfing the clip size would instantly remove suicide bombing. Nerf it to 3 or 4 clip.
I don't like the idea of them all exploding at the same time. We're trying to get away from suicide bombing, not encourage it more.
Number three I really like. Almost reminds me of Halos plasma nades (the way they would sometimes latch on) this would really encourage using them against enemies rather than yourself.
I agree that the movement speed reduction can cause a lot of troll scenarios. Maybe lowest movement speed when sticking yourself and still lower movement speed when sticking a teammate, but not as much to help counter the trolling possibilities. Maybe remove the ability to stick youe teammate all together? After all it is up to you as the player to choose to bring sticky nades or not. If a team mate really wants someone to sticky them then they should have the willingness to give up an item of theirs to use them and not rely on teammates to stick them.
Oooor even better: only allow sticky nades to stick enemies and the map. Nothing else.