The D520 is often disregarded because it was an early war fighter, and it wasn't used/continually produced. Building it will not reach new subscribers from France
Yet, it is the best France at to offer early war and was far from ridiculous as far as performances/weapons go. 1 20mm Cannon and 4 Mgs. It did produce Aces, it did shot down more advance fighters when used by Vichy and Allies alike.
France did play a center role in WW2 and as such should have it's lead fighter represented in Aces High. And I honestly think it'll be a fun plane in Aces High from time to time like the C202, I16, Brew. I was bummed out when I learned that it was discarded by Hitech's.
Comes with a variety of colorfull camoed paintschemes, even shamefull ones
As far as the D23 ... hehehe ... I'm 56FG after all ... it's maybe like the 109F4, the most performant turnfighter of the line, the Paddle Prop, the benefits of the razorback aerodynamics and the hardpoints of the Bubbletops. If you call it insignificant, you should wonder why most of the skins of the D11 are D23s.