Will truly enormous custom maps be workable this time?

[SomethingWitty]

In Civ IV, some of the mods allowed for "giant" and "gigantic" maps, but these would barely work on many computers. There would be huge lengths between turns, and computers would often freeze or crash. Same thing would happen in modpacks with lots of new civs, techs, units, etc. Early game might be fine, but by the modern era you'd be bogged down with several minute waits between turns, and always have the risk of freezing or crashing due to "memory allocation faults."

The modders would explain that this was due to some inherent, unpatchable, programming flaw in Civ IV that caused it to use way too much memory.

Is there any reason to worry this will still be a problem in Civ V?