Yes Luke had such a hook... 
But the hook wasnot used that much... On the contrary Luke was used VERY much...
Let's add Luke

I believe that in this specific  topic gameplay must be considered above all. Would we want such hooks,  and if yes what should be made to make them "usable and poppular" ? Maybe many buildings and structures should be created to allow (and ensure)  the "Total and Beneficial use" of such gadgets  (and maybe some changes should be applied to the maps,  make sure the players wouldnot use the hook to reach places they are supposed to reach etc).... hmm I don't know

Now... what would be more interesting would be to see those magnetic cables,  that were used to bring those beasts down    (<-- my opinion)

Thanks

I think a grapling hook would add a lot of new possibilites (maybe too much) to the game. But if you give the grapling hook only to specific units like the scout maybe it'll work out if ONLY this unittype can use it and not the rest of the squad. This again can defeat the teamplay. But I also think it'd be too much to include in the first releases.