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.
Other synergies include Trick of Light for fast advance, Back Channels on an advanceable trap for an economic boost, and Constellation Protocol to support advanceable ice and Mass Commercialization.
If you find any other uses or synergies, mention them in the comments.