100% agree. I've had games where it spirals out of control and becomes unplayable (like literally crashes, not figuratively, it cannot be played). Call it high risk high reward?
Most of the time I'd say "you know what you're getting into" when you pick it, but there are a couple that just give you a small number of random other abilities, and if you roll the "ability every egg" you've screwed yourself over, but through no fault of your own (kinda).
The ability system (and, let's be honest, the entire game) is more of a proof of concept than anything else. My biggest regret is how little it actually affects the core game of Snake. If you pick the right abilities, you're pretty much just playing regular Snake with nothing else. If I were to return to this game, every ability would be as fundamentally game changing as that one (though probably much less random and chaotic). The fact that it feels like you're playing a different (more gambly game) when you get an ability every egg is a feature, not a bug.
Of course, you're right that it should only pick from a smaller set of other abilities (and definitely not itself), but I like that it's unpredictable. I still want it to sometimes screw you over. If it was only good all the time, it undermines the point that it's random and you picked it.