Humm did you not see the pictures of the ballerina (aka the spit) and the iron (aka the 109) ?
Regarding the 109 FM it's not under modeled. I feel them like perfect (ok ok it lack a lot of buffeting, dyn stalls etc ..) but those are way ahead of the previous IL2 series.
If you take any IL2 moded FM as a reference of course CoD planes have lower perfs but ... it's not related anyway to the CoD devs.
They hve done a tremendous work .