It doesn't really matter at this point. If the perk system was more dynamic in that as newer variants come available those late or rare variants were perked then both the -4 and Chog should stay perked. Since HTC has abandoned, or at the very least allowed the current perk system to stagnate, then just unperk them.
Back when the Chog was getting near 20% of the kills in the arena there were far fewer planes choices. Now with the greater number of choices I don't think it would get near 20% again. However, it would be used way more then it is now with the light perk value.
While the -4 is an outstanding fighter very few 'outstanding' pilots would fly it. The -4 will be just another fast suicide jabo similar to the P-51. Very few will fight in it. They will load up with bombs, climb to 20k and rush at a field as fast as they can, dive in, then drop their bombs and either auger or runway 10 sectors before turning around to repeat.
The only 3 planes that could really unbalance the arena are the 262, the Tempest and the 163 (less so since its limited to certain bases). The rest of the perk planes should be unperked. While a couple of them are really decent fighters they will mostly get used by 'tards.
Perk points are so easy to accumulate that it doesn't really matter much except to those who think 'perk points' have some real value. These are the folks that get upset about perk values and losing perks points in the first place. What's a Chog perked 8? I could spend a whole tour auguring Chogs and still have plenty of points for the next tour.
Urchin when did you come back to AH, this tour..? Don't you have like 2000 perk points already?