I'd like to throw this around for the pro's and con's.  I expect more cons

How about a fold down front sight that locks firmly vertical for 50/200 yard zero, but folds forward (so you have a crisp sight post profile) and 'clicks' in at certain points for a 3/4/5/6/7/800 meter zero.  Or even better, 4/6/800 meter so it would be less complex with fewer clicks.  I dunno if it would even be possible to tilt the front sight post enough to make only the adjustment from 200 to 300 or 300 to 400 meters.  Perhaps Lock at 50/200, then click to 400/500, etc.  This is all definitely open to discussion.

Sorta like moving the A2 elevation drum to the front without all that bulk. Just a modified folding front sight.  Sure it would be slower than A2, but its better than a regular Arms 40 etc rear with no way of accounting for range with your BUIS.  And as long as you have firm locks at full vertical and flat, I dont see any problems with it sticking in the middle positions without you knowing.  It would just have to be well engineered.

Flame away...all opinions welcome, but if anybody makes one, I want a free sample

was it really that bad of an idea?

Yes, it was.

Do you mean something like the AK rear site adjustment?

your description is a bit hard to follow, but if I read it right.........

you suggest making a variable folding front site post for various ranges.

if so..............

while it would certainly work, the sacrifice would be cumbersome changes to a weapon that is expected to be a quick response shooter- not a--- calculate range....set front site....shoot ...adjust.. shoot

But kudos for thinking like a guy wanting to improve on a proven set up

then again I may have mis read your idea

You mean like the adjustable rear sight that no one uses?