Well, it definitely is awesome to have it against monsters, but for my games the problem has been that it is only one attack. So without buffs, you completely miss 1/3 of the time, of the times you do hit, 1/3 of those do not wound, and of the times that actually do wound, we can imagine MonsterMan is at least a 4+ save, so 1/6 of those also do nothing at all. In a game that goes 5 rounds, 2 of the torpedoes missed, 2 failed to wound, and 1 was saved :( (obviously that is not really the way math works, but it sure seems like the way my dice work). Essentially, like most of the cool things in Dispossessed, it is awesome if it works, but probably costs too much to be worth trying because you get nothing at all when it doesnt

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Are you asking to get out maneuvered and shot off the board? Probably. Will you have an awesome time and, if they dont have enough shooting, potentially still win? Definitely.
In the end, i think it sounds like a crazy fun list, and it will be pretty slow, but will really really hurt when it actually does catch anyone. It is, for sure, a good list for times when you need to rush something and want to take Dispossessed. If you want to play a fun casual game, play the ritual with a buddy and have him bring 1.2K as the defender and see if he can withstand the might of 60 slayers!
The other good thing about this list is that it will transition well if you ever want to play a mixed order. For example 600 points, you can add Ungrim, 30 slayers, and 10 longbeards. That will keep almost all the synergy you had before (90 attacks, 2+/2+), and hopefully wreck the flank where the opponent didnt put his shooting, while your 1400 other points do the rest of the things you needed.