I've been thinking about using BLU in Kamhir Drift for a while now, mainly for different dmg type and tanking MB.
BLU is perfectly fine for tojil as well, it's just not optimal. It's not really optimal in every single end game event due to SAM being too OP, and you don't need extra utility it offers to get win.
Oh and btw, don't use /shout as an indication of which job/setup is better or useful in an event. 95% of the /shout I've seen don't shout for optimal setup. For example, GEO is one of the best choice for stunner role in delve 1, since it can stun just fine AND do debuff to increase pt kill speed. I've yet to see anyone /shout for a GEO as stunner on my server. In fact even after haste2 update ppl still /shout for SCH 24/7, when you should be using RDM. COR is also one of the best choice for DD spot, with 40%~56% more attack and extra 18%~23% def down, and at least 55%~60% of MNK's output, ppl don't really /shout for this job for delve either.
I'm not saying BLU doesn't need a buff nor optimal in current delve, but I do think ppl need to stop using /shout as an indication to complain about certain job being useful or not.