Load time, with everyone downloading the map from online, would really depend on how the map is generated.
For example, Far Cry looked like it used a rather large height map for the base terrain, on top of fairly detailed object placement. On the other hand, the TimeSplitters series only allowed placing pre-built rooms onto a relatively small (though multi-level) grid, and had limited object placement as well. Halo's Forge skipped terrain editing entirely, but instead allowed detailed object placement (which people, as always with map editors, learned to abuse and bend to other purposes.)
A tiled system placing pre-built rooms, if carefully designed, could produce decent sized maps in under 1KB, without any compression beyond careful bit-field usage. The biggest fault of such a map maker is that you don't have a lot of fine control, and thus created maps will start to look similar. (The more customization you allow, the more the file size will increase. The cost in size versus the quality of customization will again depend on how carefully designed the whole format is.)
Help is a gift that one must never grow to expect. -- Willow (Witches' Brew by Terry Brooks)
I sold all my LEGO's a loooooong time ago in a garage sale.... or i should say, my mom did while i had my back turned. the *****. Games featuring anything like a LEGO-like map editor... is pure gold to me.
... i miss my ****ing damn LEGO's..... i had like.... 60 pounds worth of them!!!
Sparkster returns after 16 years in..... "Rocket Knight" My Alias for Wii Online = "Shader" Monster Hunter Tri = "Deimos"