After getting halfway to Emberlight and from Emberlight on I cannot remember EVER encountering an energy gate or a capsule dispenser.
In fact I've only ever encountered a capsule dispenser once.
So, I'm not sure how you feel about this but it does seem odd the first 8 depths or so seem to have at least 1 a level and then they just vanish.
I run into energy gates a lot on treasure levels. There is also one level that seems guaranteed to have an energy gate (stone gardens).
I have only run into one capsule dispenser, and that was on the tutorial area :|