Do YOU think we'll get a new Tank and/or Healer in 4.0? And vice versa.

[Ultimatecalibur]

Semantics. BRD+MCH is justifiable just like BLM+SMN, PLD+DRK or WHM+AST, just not optimal.

Yep, justification is not optimization. All a group needs to justify a comp is to have players whom prefer to play those classes and successfully clear the content. Any justifiable raid comp should be 2xTanks + 2xHealers + 2xMeleeDpS + 2xRangedDpS with each sub-comp having 2 different jobs in it, but due to some synergies being better between certain classes not all justifiable comps are close to optimal and not all sub-comps have a near/semi-optimal comp.