Be careful what you ask for... think about it a bit. What is the reason to ask for this, is it to make some of the earlier rides more competitive, to remove an unbalancing ability (see C-Hog for reference) or is it to increase the variety of planes (again refer to C-Hog) you see in the MA? I don't know that you can force any issue by perking more planes.
If you are perking the planes based on competitive issues then the only fair way to do it is to work from the least capable plane (which might be something like the Hurri I). That is going to set the bar awefully low for perking, things that are only average now, like the 190A5, are going to be uber to a Hurri I. If you pick another level then you are not making it any more fair in the MA, you are just re-setting the point at which you think "fair" should start. People still won't fly things that are sub-competitive if there is something that is "better" that they can fly for free. If you set the bar at the 190A5, no more people will likely fly the Hurr I even though it could be considered "more competitive" as compared to the standard. It'll still be completely out-classed.
If you are trying to remove an unbalacing ability of a specific plane, then that ability should be fairly unique and unfair. Name what that is in the group of P-51, La7, and 190D9.. I just don't get it. They can all run fast or catch you if you are slow? 2K of alt pretty much negates that advantage, I had a Hurri C catch my La7 the other day because he dove on me and caught me. None of them is overpowering in any way, the P-51 is the most capable of the lot, on average, but isn't the best down low. The La7 is the best down low but sucks even at mid alts. The 190 is a fine ride, good in both, but not the best in either. Sounds like they are all similar in ability, just tuned differently for different altitudes. You can't claim any one of them has a clear ability that is unbalancing since they all have a similar ability.
If you perk the planes based on "popularity" then you risk taking the following planes immediately out of circulation for newbie pilots (since they won't have many/any perks). The P-51D, 190D9, La7, SpitIX, SpitV and N1K. I honestly doubt it would seriously hinder their use by veterans since they tend to have perks built up and land their planes more often. The average newbie probably lands 1 sortie in 10, the veteran can probably land 8 in 10 if they wanted to. So, you end up with veterans almost un-effected while they get to club newbies in lesser planes. Honestly, the newbies need the powerful planes more than the veterans to make up for a lack of ACM skills.
Secondly, how would it affect the usage patterns in the MA to take these planes out of "free-ride" use. Well, you'd see alternate rides pop up that were just as popular (or more so) and you would have to ensure that these new rides didn't encounter the same problems. Look at the P-51B, for example, anyone who was a P-51D pilot would switch to the B, a lot of 190 and La7 drivers would also. The P51B offers EVERYTHING that the D model does except it comes with only 4 guns, not 6. Same speed, range, etc. It would HAVE to be perked at the same time or it would just become the "new D". Thus, there would be no free P-51's anymore. And how about the Spits... well, the XIV is a perk for sure, the IX is a perk then, the V is super popular (1% less than the La7) so it'd have to go and the Seafire is just a SpitV... that leaves only a Spit I. That would surely piss a lot of people off since the Spit I is not really a competitor. So, for two of the most famous and popular planes in the MA you don't have the P51 in any model and the Spit is what would generally be considered a target (imagine what even a Zeke would do to a Spit I... ouch). that's not to mention other planes, like the TYphoon and 109G10 that would now be even more popular because they pack a HUGE speed advantage over the test of the field, do you take them out too? I suspect you would be forced to since you removed all their contemporaries which had abilities to deal with them. A G10 would appear like an Me262 to a SpitI. Others, like the new hardended P-38 would pick up huge followings too and probably be destined for the same treatment. Did this increase variety, no, probably not, it most likely decreased it as more and more planes got the similar treatment.
I just don't see how it could work. In the CT the circumstances were different and light perking worked. Nobody had time to build up a tonne of perks because they were reset each week (which was a terrible idea for the casual player) and few newbie pilots even bothered to come in there because of the increased difficulty (short icons, no dar, etc). It also led to a lot of strato-dweeb'ism because people always wanted to protect their perk ride (if only 1-2 points even) by ensuring they were the highest thing around. It also required that heavy bombers be perked too... I bet lots of people wouldn't like their B-17's, Lancs, Ki's and B26's perked, leaving only the TBM and Ju88 (which have about a 2 second survival time against opposition).
I appreciate the frustration of some people about the hordes of only 7 types of planes in the MA (or whatever that number may happen to be) but it's pretty hard to force it to a larger group by knocking out those 7 and trying to even out 8 new ones (or more). You are far more likely to knock out these 7 and and end up with fewer. While the C-Hog perking worked wonders, it also made it a relatively rare plane in the MA so how would perking these others make that any different. It also meant that very few newbies ever fly the C-Hog, they save their points for Tempests, SpitXIV's, and Me262's.
-Soda