There are tools that output (somewhat) standard formats formats for things like characters and monsters/mobs. DnD4.0 being a good example. Who it be 1) use-appropriate for rpg.sx to allow this and 2) Is it technically feasable to implement an XML import/support?
Not feasible for anyone actually on this site. We could request it of the core SE team but it would need to be something that's not specific to one game, D&D 4.0 being a good example. I'm split on it being use-appropriate - this is a Q&A site, not a work-product-sharing site (just like SO isn't a code sharing site). I guess I have to say "sounds of dubious value and probably not what I want to spend RPG.SE political capital on getting the SE team to implement."