Newer machines also have under playfield magnets which can also add randomness and fast flung balls. IM, Avengers and ST to name a few.
excellent point forgot about this, but as a player, do you have a say in whether to risk a shot through the magnets to achieve a reward like good points or are they a bit like sewp1 where you feel a bit ripped off playing well and then a magnet just drains your ball. I haven't really played the games you have mentioned
I actually get a rush or high playing the games with magnets. They are good during multiball when there is a lot going on and your mind is on strategies and balls flying everywhere when a magnet fires a ball at a rapid rate. The late Stern pop bumper area is a relief sometines during multiball as it gives you a bit of a break from too much action. Loosing a ball from a magnet during multi ball is no great loss as you may get it back if timer is running or you still have some balls in play.