As most of you probably know, MoM had guardians at important locations. Elemental doesn't go the guardian way but has some technology requirements. Very civ-like there.
I would like to have guardians at least a possibility in Elemental. I think they add to enjoyment because they provide intermediate goals. Right now if you see a lost library, you can just pop a settlement next to it. See a shard? Pop a settlement. I don't find that very exciting, the only thing that isn't evitable there is if an opponent gets there first. And what if you don't have any targets for quests or anything worth settling next to? Do research and something will randomly appear somewhere. Pop a settlement. Did that really reward good play from my part?
With guardians I would have to gather a force. With scouting intel, I could even make a tailored force to defeat them. This would be an additional goal for me, thereby increasing the amount of meaningful decisions available to me. Instead of having new locations appear randomly, I would have more knowledge and more goals available from an earlier point of time.