Heuristic detection is iffy IMO, because while this might look trivial now (=> before cheaters optimize for it) false positives could easily ruin the user experience after a few rounds of cat & mouse: Even if you manage to keep sensitivity high (detecting >90% of cheaters), if you have like single digit percentages of cheaters and false positives, a lot of your bans are innocent.

If you keep the heuristics "tolerant", on the other had, you end up perpetually chasing in a cat-and-mouse game, and a lot of cheaters go undetected inbetween detection upgrades.

I feel heuristic detection is a "metagame" that developers don't really want to engage in, because you basically can't really win and it's perpetual work/spending.