ok, first of all hi everyone! I was a member when RRU had just started out and we were still trying to figure out how to mod RR haha... I've been gone for a long time and even lost my original account, but I'm back!
Hard to belieave that DDI are actually pushing to make a new game happen, it's so exciting!
Here are my two cents in brainstorm fashion, I'll add more if I think of anything
Monsters: I think monster spawning could be more similar to minecraft. have them spawn randomly once and a while from dark and unsupported destructible cave walls, maybe even lava! But also let them spawn from spawners (like minecraft's dungeons). This is also similar to how sligs spawned in RR, though I would have the option to use tnt on the spawners to seal them shut. The spawners could randomly appear in unlit areas or unexplored caves as well, so that closing one wouldn't mean being safe forever.
I also think we should have giant spider mobs, that can bite and poison miners and down lay webs that slow miners down for example.
I also support the idea of monster bosses, think of a giant rock monster made of energy crystal (with electricity powers), giant lava monster that can make miners and building catch fire and ice giants that can freeze miners and machinery in little ice blocks for example!
We also need giant mushrooms! thes could be hardous and release poisonous spores that make miners sick! they need to be destroyed by tnt or a vehicle and sick miners will have to go to the medical center or they would eventually die.
Buildings:
the geological center needs a revamp and so do mining lasers.
the support center should be divided into medical center, air support plant and food dispensery. the medical center heals rock raiders and takes care of poison (from spiders and mushrooms) and burns.
Electric fences.I propose that electric fence towers can be place far apart (e.g. up to 5 blocks apart for them to still protect the space in-between). To counteract this feature, the towers or nodes will be vulnerable to ranged attack by monsters if not upgraded to having offensive capabilities (which should be expensive).
Power stations to extend the range of power paths which should be limited to something like 15-20 blocks.
Building bridges and being able to dig walls from a floating vehicle should be taken for granted.
power paths should protect against lava erosion if reinforced and powered.
Miners:
Specialized miners should wear a different outfit to be able to make them out from the normal guys easily.
Medics! Guards!
Graphics:
at least support for bump mapping pleeeease! tesselation would be even better