Should mention that there's 3 entrances for vehicles on Hourglass, being the left, hill and right side whereas Niagra only has 2 vehicle entrances, the PP sides, and AGT/OB side on the left side of the bases if you're looking towards the ditch, meaning less room to rush. So, nothing happening in the ditch? Oh, must be people on the left side.
In addition, MRLS can shoot air and arties can shoot bar from the overhang area in the middle on Niagra (Snipers can do the same but to infantry). On Hourglass, MRLS can shoot hon or ref so easily AND B2B!, arties have a bit of struggle due to the hill incline but they can shoot WF or ref without getting spotted by AGT. (Most games I saw on Hourglass before hill camp rule was MRLS winning via hill or arties winning via hill, making hourglass pretty much a very VERY short game, meaning there's no point to play the map if it's just going to end too quickly, which is why I agree with the hillcamp rule.) Then again, same thing can happen on Niagra, MRLS/Arties can just easily kill PP, and then it's a short game from there. That's just my observation.