I'd like 2 sets of rules, I believe JD has this where you can start a game that's pure Multiball or something.
Just think if there were two sets of rules, you could get more enjoyment out of a game. For example on XMLE there is options with stacking on or off. There could be more options, or even an optional entire new rule set.
Like if ST was like it is (normal rules) but there was a lightning rule version that plays more like IM where it's easier to complete, but maybe the modes un-light when you drain a ball so it can become more of a one ball short game. Maybe the whole object is to light one mode three deep with a super JP as a reward (that's it but the progress does not save between balls). In some way using the existing mode rules but changing the master code it might not be too difficult to tweak much like some options in the menu (on/off can make a game play differently).
The key is there is two sets of rules for one game. One can be a simple rule set not necessarily super deep but more intense quick game. If a game plays super long like SM or LotR maybe it's more of a 'hurry up' mode that is set just on 90 seconds per ball (ball drains at the end of 90 seconds) but is aimed for maximum points not necessarily looking for a long quest.