With your Logic Gate it is possible to set up the most and easy logic elements but when it comes to a bit more complex stuff it does not help that much.

On the other hand there is RF-Control, but in my opinion thats a bit overkill for the two things I am asking for:
-1- RS-Latch
A logic element I am using quite often but in 1.10 there isn't one handy. Charset has one, but its not really maintained and the RS-Latch is disabled atm.
In RedPower² and Project Red, it allowed four different states: regular (remember), inverse (remember), regular and inverse. The remember version did also send out a redstone signal on the input side.

A simple usage is some kind of time buffer. For example you use two capacitors. The first emits a redstone signal when empty, the second one when fully charged. Now the RS-Latch can trigger a generator based on a redstone signal.

Project Red Wiki about it: http://projectredwiki.com/wiki/RS_Latch

-2- Redstone Emitter
Another simple thing that I really miss. A simple block that acts like a redstone torch, but emits a configurable redstone signal.