Whatever future model we end up using, it should support some robust form of handing reasonably large maps.
One thing the DDT is finding is that once you go with larger mobs, your sense of the map size shrinks dramatically. Areas that seemed huge before now seem tiny.
And playing Diablo, which uses mob sizes and graphics that are I think a pretty good model for Future BYOND, I realize that the space of ground I cover in a few seconds is the size of a large map in BYOND.
After much observation, including during times of lag when the seams show a bit, I've determined how Blizzard does their Diablo maps:
They create a number of large map chunks (you could think of them as areas) which can be rotated and connect to each other seamlessly, then they specify the map by just storing references to those chunks and displaying them when they come into view. Internally, a zone is probably stored something like this, assuming 50 different area types:
30 EAST || 43 SOUTH || 21 SOUTH || 15 WEST
In this manner, the area takes up no memory until you see a part of it, at which time it is displayed and populated, and often it's a duplicate of other areas you have in memory. It's as if they were treating each large area the same way we treat a turf.
All the places you've loaded stay loaded (including mobs and dead bodies).
It's possible to imagine how BYOND could be extended to load areas on demand similar to this...though I wonder, how to games like Diablo store all that data in memory? To store an equivalent amount of space in BYOND would be pretty huge...or maybe they are taking up a huge amount of memory and that's the basic answer?
Anyway, it seems like a robust ability to load portions of the map dynamically is important, and the ability to keep reasonably large amounts of map in memory at a time, possibly by supporting an "area definition" that is similar to a turf definition that can be displayed on demand, if there's any way we can swing it.
One interesting point: Even Blizzard doesn't try to have all their mobs be active all the time. Once an area has been loaded, the mobs stay in their initial location until you stumble on them.
Hmm.