According to Overwatch’s principal designer Geoff Goodman, Roadhog’s hook ability will be nerfed very soon.
On the shooter’s forum, Goodman details upcoming changes to Roadhog’s ability: “The hook victim will now move into the position directly in front of Roadhog, rather than just a straight line towards him. There is a cap on how far ‘to the side’ you can be pulled, so you can’t just hook someone, spin 180, and dump someone off a cliff.”
Goodman also states that he won’t be able to hook someone whom he can’t see and a persistent line-of-sight check will cut the line between Roadhog and his victim if they drop out of sight mid-hook.
Goodman stated elsewhere in the thread that he thinks Sombra “could use a bit of a boost,” suggesting that she may get a buff in the near future.