However, setting that aside, there's still the Corner-based vision that has had a couple recent posts. Workarounds exist, but for actual support of that type of vision (similar to how MT can do one-one-one diagonals), corner based sight is needed (again - needed if we want true D&D 4th Edition Line of Sight compatibility).
Yeah, that ought to be a non-default option, at the very least, since it is pretty necessary if we are looking to put out a system-agnostic tool. If there's a significant performance hit, a warning pop-up with the "Never show again" option would be sufficient.
In 1.4, of course.
Yeah, definitely non-default. I would treat it exactly as the ONE_ONE_ONE, ONE_TWO_ONE, and related movement metrics. Yes, they are compatible with D&D, but they're not "d&d movement." I'd have the default vision measuring be from the Center of Square, and as an option, Corner of Square could be enabled.
I play D&D 4th, and I don't actually pay much attention to the vagaries of Line of Sight in the game (center versus corner don't befront me none, so long as I get my rent next Friday). But for people who want it to be "proper," I think it's reasonable to do it if it's possible to do.
After all - MapTool does not explicitly support any given game system, but I don't see a reason to refuse
to add a feature that supports one unless it's a) not worth implementing or devastating to performance, b) actually prevents
MapTool from being as system-neutral as it should be, or c) legally suspect.