...to Google Experimental Search as an option to use [although its still a separate product in Labs and accessible by the ?complete=1 parameter).

google.com/experimental/index. ...

More importantly though, why can't I add multiple experiments together, my perfect Google would be Keyword suggestions, Keyboard shortcuts and "Left-hand search navigation" in one.

<<Why can't I add multiple experiments together?>>

Because they could interact in unexpected ways and you should give feedback for an experiment, not for a combination of experiments.