Yeah I agree the barrance is currently out of wack.
If I need the last 2 slot of my party filled and I see a Geo, a Brd, a Mnk and a Blu seeking, then I would most likely get the Geo+Blu combo unless I need Lullaby from Brd. The Mnk is pretty much sitting in the corner now.
However, it's important to see what a job can do and what really makes it unique. You need scenario when certain job combinations are better than others but you can't just make other jobs invalid - inefficient but not invalid.
We don't need the "same thing with different names" like FFXIV.
We certainly don't want to fall into the trap of "They are different things with the same capabilities" either - because it's the same as the previous one.