The TGM randomization algorithm is also pretty elegant. 7 bag is a bit extreme, it gives you such a perfect set of pieces at all times that it's genuinely less challenging and fun. TGM's random piece algorithm is a lot simpler: the randomizer has a 4-piece history window and it tries multiple times (IIRC, 6) to find a unique piece that hasn't appeared in that window. It is initialized to SSZZ to lower the odds of starting with an S or Z early on. (~~They also use the Mersenne Twister as their PRNG, which was a pretty good PRNG in an era where many games still used LCGs.~~ edit: Apparently, they do not. Don't ask me where I got this, I have no idea.)
Now of course I'm not sure if it matters at all for this particular game since it isn't really a Tetris clone at all, but while TGM is a well-known cult classic for people deep into Tetris it's relatively obscure outside of that circle (and presumably outside of Japan.) The Tetris Company is very strange about licensing and has apparently, as the legend has it, blocked and forced changes on TGM releases for a very long time due to the fact that it doesn't fit with the Tetris guideline rules they enforce in an oddly totalitarian fashion, probably suppressing the game even further in an era where speed games and competitive gaming is a lot more popular.