MSH was a bit too much for the Saturn's RAM (and the PSX version has even MORE slowdowns), so even with the butchered animations, there are lotsa slowdowns.
Using the 1MB RAM cart (no, it does not make full use of the 4MB cart because it didn't exist when the game was made - only the SNK 1MB cart was avaliable) the option "3MB MODE" will become avaliable.
If you turn it on, you'll get extra animations. It isn't the full arcade, but things looks nicer. As example, most characters will have an actual "walking backwards" animation, instead of merely re-using frames from the "walk foward" animation in reversed order. The gems special effects also become more fluid. But the framerate doesn't change much (it becomes a LITTLE faster, but slowdowns still occurs with big characters os moves).
But, I noticed that using a RAM card with the 3MB mode OFF actually eliminates most of the slowdowns, but won't improve the animations. The game become much more enjoyable that way.