Yeah, It's silly.
Sometimes I like to play stealthy too. If I find myself in a corner of a map, with enemies coming from both sides... how exactly do they expect me to survive without sitting in a corner and hoping they don't spot me?
It's just silly... There's no point in using the perk, might as well slap on Counter UAV and use a better perk than Ghost.
I think you're overreacting a bit, just like everyone else, you don't see the advantages and few little details.
Has someone said that how sensitive it really is, like if you just move from side to side while the UAV is up, will the game still consider you're holding still?
Besides, even though I hate campers, I think it gives you a whole new way to use the perk, remember that confusing others becomes easier, enemy UAV is up, you hold still, they see you on the radar and attack, you have huge advantage if you can hear the guy coming or know he is nearby, just try to have good timing on the moment you start moving and your "hunter" walks to the spot you were while you're sneaking behind him...
Of course I know that there are equipment that might make it harder, but c'mon everyone loves a little challenge, you just have to find the positive sides of the perk and learn to adapt.
Also, why are everyone talking like there would constantly be UAV up, well most likely there will since people love to spam it, but still, you don't need stealth perks to be stealthy, just having perk that decreases the sound of your movements will help.
And your suggestion about ghost showing you in the radar if you move, well it isn't bad idea, but it would just increase the camping.