I agree about both of those things, but- Some games sound better with one, some the other, some it doesn't matter. Just be careful, because certain games that use a lot of custom SysEx instruments, ala Willy Beamish, sound WAY different (a.k.a. wrong) on the CM-32L.
Now I'm really only talking Sierra games, obviously many other companies used the MT-32/etc
What you say is quite true. Especially games from Sierra and Dynamix have a few sounds that only sound right on the MT-32 (Old). Lucasarts on the other hand seem to have used a LAPC-I / CM-32L. Especially Sound Effects can have quite noticeable differences like the spitting sounds in Monkey Island 2 or the stamp sound in Heart of China.
Wing Commander is another game. Here the firework (the final loud BANG) will clip on non MT-32(old) units because of the change to the volume control.
The CM-32L however is very quiet, I think it's the quietest card of all of them.