G-10 was a terror in pre 1.03 FM. All planes bled E at greater rate than now and G-10's ability to recover E was very pronounced.
A P-51 could make a bounce, pull too hard and next thing you had G-10 climb to it and kill it.
With newer FM G-10 lost this dvantage, as well as becoming less stable in low speed flight. Its high speed characteristics were always poor.
This, and increased arena number have made G-10 flying much more difficult. The plane is best utilized when fights slows down, and G-10 can use its power to increase its E while opponent can't. Slowing down, however, is very dangerous in a crowded arena and this is what AH is today.
Even if you stay fast and manage to deliver hits at 400+ mph, they will not be enough and you will have to make another pass. 190 works much better in this aspect.
G-10 is still a potent plane, probably best used in attacks from below and unseen. E tactics stillwork, especially in limited numbers environment.
Planes like Spit XIV and Lame-7 outperform G-10 in certain aspects which used to be its advantages.
IMO, Dora and Ta-152 are much better arena planes than G-10.
Still, G-10 is a great dueling plane.