Havelock

It would be nice if we can set the initial state of switches. (e.g. A switch that starts on, instead of off)

The ability to toggle (like a switch) whether or not the logic splitter stops events or not.

Personally I use heaters as well, but like Lurkily said the heater remains after burning the other pieces. I also don't like the fact that the burning pieces are potentially hazardous.

A block which on activation dissolves/deconstructs attached blocks. Can be useful for cleanly disposing of factory creations which no longer serve a purpose.