I've spent a bit of time in the 51 leading up to DGS. It's a wonderful bird, and it's easy to understand why it's flown so much. It does everything well, and only has two flaws (climb and acceleration). While my own personal wish would be for EVERY plane to have some sort of perk (Yes, even the I-16

), that is probably a bad idea if we actually want new players to come in and stay a while.
This game has a pretty steep learning curve. Even for those of us that come in with some flight/combat sim experience and historical knowledge, it can be frustrating. Planes like the 51 and Spit 16 probably need to stay unperked if for no other reason than to give noobs and the less dedicated a nice ride to compete in.
I like the thinking of a few that have posted already. When I'm not in a 51, I see other 51's as perk points just waiting for me.

Embrace the 51 scourge. It's better than worrying about it for sure.