Well, like I said, lots of Filmation shows had the same few people doing all the voices -- and then of course there were the older cinematic and early TV cartoons that had even smaller casts, like Mel Blanc doing virtually every voice for Warner Bros., Daws Butler & Don Messick being nearly the entire ensemble of Hanna-Barbera's early shows, etc. So recognizability isn't a deal-breaker for me, since it's what I grew up with.
Oh sure, me too. I think the difference is, those guys (Blanc, Butler,etc.) were for the most part strictly voiceover guys and could vary their voices enough to make the characters different. That's how they made their living. The Star Trek cast were not voice actors, so reusing them was a cost cutting decision rather than a creative one. When you hear Sulu coming out of Koloth, it's not because Takei was the best guy for the job. I would have preferred Doohan because he could put a little more variety into it. But, as you say, these were done quickly and I admit that I am totally nit picking. My love for Filmation is boundless.
Well, okay, not so much for Hero High. That was just awful.