In terms of its numbers, Otoroshi has a gross tax of 6, (and a net tax of ~4), which are great in relation to its rez cost of 2. However, Its weakness lies in its subroutine, which the runner may allow to trigger.
Otoroshi can be placed on a remote server to threaten a flatline with Project Junebug or a rig wipe with Neurostasis if it is protecting an advanceable card, (making it ideal in a shell game glacier).
Otoroshi can also place advancement counters on cards that cannot normally be advanced, and can be combined with API-S Keeper Isobel to become an economic booster, making this ice very efficient and impactful.
If you find any other uses or synergies, mention them in the comments.