I would like a "soft" VNAV mode. where not only vertical restrictions are meet, but where a max 1000'/min climb/descend is used in RVSM. and ie a 2000' rate 2000' before selected level, 1000' rate 1000' before level off is commanded in TMAs ie. FL150 and below...
should be fairly simple, then you could look at what this will do to fuel usage, and so on...