One thing about Violator's proposition of having multiple tools, it then more often seems to be the case you wanted a Ki-84 while you had already upped a K-4 etc. You can't alter the tools to the job once you've taken it out of the box and offered fights and situations were always fluxing
That's my experience quite often, the fight I took the best tool for the job at the time ends, and then a different set of enemies comes in.
If the enemies are committed to fighting, the all rounders like the KI84 are great. However if you run into a crowd of one pass and reset ponies, doras, and typhs, you're either going to have to be great at fighting from the bottom/getting shots on overshoots or you're going to have a bad time.
If I'm in something fast to run down the one pass and reset ponies, doras, and typhs I feel like I often run into a swarm of KI84s, Spit16s and Yak3s with alt on me. Just the way it works out.
Generally speaking if I don't know what the enemy's up to, I will use a K4. It's faster than a lot of the all rounders and its main downside is the gun's not that user friendly. But it can dogfight decently, keep up with a lot of planes, and will take out bombers depending on how good of a gunnery day I'm having.
Several planes turn better but they aren't as fast/don't climb or accelerate as well. Those two attributes go a long, long way for me in the MA.
Wiley.