F4Us got uber-fied in the airflow update. It's not right. They had a lethal stall and in this game float like a bubble.
Don't stall fight a F4u, period.
Considering that, the P-51s are still competent killers. You can't turn fight, and you frankly never should have been able to. I'm not saying you can't turn, I'm just saying don't fall into the slowest-tightest-turner-wins mentality.
They turn pretty well, zoom, dive, etc. All those staples that you remember. But *every* plane flies a little differently now. The airflow code is much more refined, save for a few questionable things here and there.
P-51s excel in many areas. Turn radius isn't one.