That's the main thing I don't like Kaboom. I don't want repeated patterns. You can't keep from memorizing certain patterns, even if you don't want to memorize them. As I've said about a billion times before, many Activision games are pretty to look at, but too many of them seem to be devoid of randomness.
The thing I really like about Random Terrain is that he is random about anything except his defense of randomness as it comes to playability -- in that area, he is very consistent (that is genuinely meant as a compliment, RT - I respect consistency of purpose, and standing up for what you believe in, and you do both)
The thing I really like about Kaboom! is the exclamation point. Beyond that, I love the look of the game - it was the first Atari game I ever owned that was great looking and great playing, and wasn't a "looks almost as great as the arcade" kind of great -- it was great standing all on its own, and it was the ultimate best version of the game.
The other thing I really like about Kaboom! is that it plays better on real hardware, as opposed to an emulator, than any other game. The fast twitch action of a (working and well maintained) VCS paddle playing Kaboom! has yet to be replicated anywhere.
Lastly, I really like how it is a really tight game - single purpose, only 2k code size, easy to figure out, easy to learn, hard to master (yes, even without total randomness ). Also, the lack of total randomness gives some reward to sticking with the game and practicing - it still gets so hard so quickly that even knowing the patterns doesn't give a massive, original arcade Pac-Man sized, level of advantage.