I'd like to see n-gon support in Terragen. This would basically solve all problems resulting from exporting objects using this feature, then, seeing a cylinder cap missing or glitching out.
While it's no biggie and other solutions (triangle fans) may be used as a workaround, one may still get forgetful and have to redo the objects.
Also... ehem... could we bring the spherical camera into "creative edition"? Pretty please? :D ;)