i have to agree with you there they should try to keep it mining themed and throw in some transparent peaces for the monsters i´d like to see new peaces being made for the monsters that would allow us to make custom ones, but they should also give us them in a lot of different colors, but maybe they could add some sort if liquid as the miners would have to get for their vehicles for them to run.
i´d like to see some sort of a bad guy human faction who would have their won vehicles and use the crystals for something bad.
and i´d like to see more valuable items then just the crystals such as: iron, gold, copper, any kind of underground material. and having small sets that is just like battlepacks were you get 4 minifigs with some extra tools.
overall i want to be able to emulate a similar concept to the pc version of the rock raiders game with the theme so like: the miners need to gather crystals for researching so they can develop new weapons and buildings and upgrade their economy, oil to keep vehicles, buildings and turrets running(cause they´er gonna need turrets to protect themselves against attacking rock monsters and other hostiles down in the mines), gather iron to upgrade weapons and tools, gold for credit to build up their economy and defenses and all that.
as long as LEGO brings us sets with enough stuff to do just that i think it´s going to be awesome:)
may be a lot to ask for but hey, we can always use our creativity to make that happen our selves