One or some of the modes should incorporate  some sort of countdown as many of the episodes did with people trapped or something about to explode.  Hitting a certain target or sequence of targets could maybe extend your time to complete the mode or extend the length or number of multiballs.  E.G  Hit a target to ask for backup from another Thunderbird i.e. launch another ball or something along those lines.

I tend to agree with concentrating on the vehicles and equipment over the puppets.

A video mode is always good as well.  

I can hear the countdown as well releasing some captive balls from around the playfield. 5 - ball gets loaded  4 - another ball gets loaded somewhere else 3 - another one is loaded 2 - another one released or loaded 1 - same again.  TBs are GO and all hell breaks loose with 5 balls launched from all over the place.  Something like the spinning magnet disc on Twister may also work.