There were no new healers or tanks added in 4.0 so they could focus on the current ones, yet WHM and DRK still need to wait until 5.0 for adjustments. BLM/SAM only got properly buffed at the end of the expansion and that was potency changes. Time and resources should be diverted to BLU so there can be a fourth caster DPS? You'd still have players unsatisfied. Either BLU is broken and 1-2 of the other casters complain about being irrelevant, or it's weak and is met with "BLU DOA lol". MCH is a full job yet hardly anyone plays it and just like WHM and DRK needs to wait until 5.0 for adjustments. You can't say BLU wouldn't be designed in the same off-putting manner.
Yeah I'd like BLU to be a full job, but I'd also like twice as many EX trials and savage to be extended to 10 floors while having the same amount of content they normally do.