With all the hoopla on how Kitkat was intended for low spec phones...

[Suspicious-Teach8788]

The video stuff was hacked from the GNex, I think, due to that device using the same GPU (higher clocked).

A lot of stuff from older versions can be ported right over with little issues. They were building 4.4 for Crespo (Nexus S) on CM right from the beginning.

So you use a nightly and judge the performance based off of a old phone that isn't even supported by the chip set mfg anymore? Sure that makes plenty of sense and trying 4.4 on a single core CPU probably seemed like a good idea too I bet. This is foolish

Typical misconception of a nightly. It doesn't mean it crashes 24/7. Nightlies just mean commits are still coming through and it's still on the nightly branch. It could likely be bugged as hell or it could be just as stable. CM 10.2 stable doesn't mean all bugs are ironed out, and nor does Android 4.4 stock. Heck, look at how many bugs persisted in Android 4.2 on the Nexus 4, and many never got solved.

There's no way you can make a general statement saying that any custom ROM = misrepresented performance. It's YMMV, and I'd be willing to bet a Galaxy S1 on a custom Kit Kat AOSP based ROM today will be pretty damn similar to how it would've run had Google actually rolled out 4.4 for the Nexus S.