The Dora turning *substantially* worse than the A5 is one of those AHII urban legends. Certainly the sustained turn *rate* is as good or better.
The 190 line follows the same upgrade path as all other birds. It gave up maneuverability for acceleration and top end. Im not sure how you are defining "substantially" but here are the numbers:
A5 Turn Radius, No Flaps: 787ft
D9 Turn Radius, No Flaps: 846ft
A5 Turn Radius, Full Flaps: 584ft
D9 Turn Radius, Full Flaps: 627ft
For purposes of comparison; the P-51D's full flap turn radius is 633ft.
Low-alt engine performance isnt as far off as you'd think, either. While the Dora maintains an acceleration advantage, the A5 outclimbs the D9 under military to about 6,500ft and, under WEP, the Dora maintains a slight advantage and a brief trade off occurs at about 4,000ft.
That is, keeping in mind, that the numbers are from tests with MA default "full" loadouts; including the outboard MGFF's in the A5; which no one takes, anyway. The reduction in weight would probably improve the A5's position by a good 5%.
It's also superior in rate of roll, which is a highly undervalued asset. I dont have numbers for it; but I'd bet that the A5 has the fastest maximum rate of roll in the game at nearly all speeds; with the Jug perhaps closing in at extremely high speeds (475kt+ dive, for example).