Neither the F4U or any 109 is an easy mode plane. The fact that it is hard to stay fast and not get picked in both planes makes them difficult to fly. The 109s cannot dive, huge crutch, the F4U doesn't gain speed easily, huge crutch. The level of SA in both of these planes is significantly greater than many other easier to fly planes. On top of that, you have to learn the fighting styles of both planes and be successful at them. The fighting styles for both planes takes some time to learn. Shooting 50 cals is a lot different than shooting a 30 mil. You have to employ different fighting styles to use the guns to their most effective means. In the 109 you have to slash attack and make quick angle deflection shot. Most haven't learned that. In the F4U you have to gain the 6 and sprey a 2 burst. In either of the planes, you can get picked easily by not shooting the guy down quickly enough and continuing to engage even though other con's are on their way. This makes it difficult to get out of the fights thus makes it hard to be successful it. Most of the time in either plane, you have to make 2 or 3 slower passes and kill your speed to get the kill, this is bad when 2 la7s are on the way to get you.
M2 vs Mk108 your argument there is wrong, if Bustr shows up he will show you that the MK108 has some of the worst qualities in the game(I believe the only weapon with a worse drop in the Hurri 2 Ds 40mm) M2 > MK108 any day...now as far as fighting styles, slashing attacks, saddling opponents...I used to say aircraft has something to do with that but in the end it's all ACM, I can use slashing attacks in a hog and clip different parts(if not shoot down completely first pass because M2s are very lethal) and I can saddle an opponent in a K4 and put a tator in his butt, ACM is all about maneuvering your aircraft in a way to kill an opponent....Why I think planes are easy mode is because they do certain flight characteristics in a certain way which makes ACM easier to do in the MA. (F4U has a fast and maneuverable dive rate so BnZ is VERY EASY to do in it)
Most of your arguments can be said for the same planes you and others call easy mode.. "you can get picked easily by not shooting the guy down quickly enough" That applies to all planes.....
No you don't have to slow down "most of the time" if you are slowing down the problem isn't the plane...it's the pilot. Now are you slowing down because your trading speed for ALT?
Views in both aircraft do make it harder for SA(Did they update the views in the hogs??? I feel like they are better these days") but look at the LA7 compared to a K4, their views are comparable.
109s do not dive well.....rgr tracking(I fly them enough) but it's acceleration does make up for it a bit
F4Us don't accelerate that well.....rgr tracking but the thing dives like a boss and can maneuver at high speed (Spit 16 can't do that)
My list of easy mode planes(top 10) non perked (Just so everyone understands where I'm coming from)
Spit16
LA7
P51
N1K
F4U
Dora
KI84
yak3
109K4
Typh