Multiple/All Jobs 50 going into ARR – What city/class will you start on?

[SidRheingold]

That means all that Main Story EXP is going to go onto my CNJ/WHM which is 50. Really, a complete waste of EXP, right?

Not a complete waste!
While the Level Cap is still 50, you now gain EXP towards the next Level.

Example:

Lv50 45.000 EXP / 565.000 EXP

You can see this in the last Producer Letter No. 48 (EXP bar).