While it's true bard/mch is parsing badly compared to other classes, are pretty much a requirement due to their utility. You can't afford to run out of TP on a high of a damage check as some of the Alex bosses.

DRG while plentiful is parsing the highest so I see many PF groups looking for one.
SMN is another one I often see people looking for.

For healers almost every group uses WHM/SCH composition, AST is terrible for progression atm.
For tanks, every group needs a WAR due to their OP tank dps. PLD is generally sought over DRK, but certain fights it's the other way around.