Using the words..."good enough" infers that there is room for improvement. And while there probably is, the two most important questions would be:
How much would you need to spend to see a substantial improvement in the mixes?
Would that expenditure of cash really be worth it? (aside from bragging rights)
IMHO.... if what you have now is giving you satisfactory results... there would be no need to upgrade the monitors.
"Satisfactory" being defined as: broadcast quality mixes that compare well to the mix quality and sound of the stuff on the radio. Everything in balance, and sounding good on a variety of players.
To me, that's "good enough"