...but the difference is hardly noticable
I need to disagree. IMO, the differences between the F4 and the G2 are not only noticeable, but significant.
The F4 is just a sweet ride - no other way to say it, really. The G2 is more of a compromise, trading that perfect balance for more top end. While thats all well and good, in the MA, you're still flying a mid-war aircraft and the speed increase over the F4 still doesn't place the G2 amongst the Spit16, 190D, 51D, La7, etc, etc, crowd.
Since most MA fights tend to funnel into a never-ending yank and bank (See:
"109" = think: "Cant turn"), sustained turn performance and stall characteristics are important - both of which favor the F4.
On the opposite end of the spectrum, if you dont want people to be able to run from you - a problem in both the F4 and G2 - and if you want to E-fight in the vert against late-war A/C packing big HP, the K4 is perfectly adept at both roles while the '43-'44 109G's (to a lesser extent the 14) dont really do anything better than any other aircraft in the set.