Riot you have the technology now and the know how.
How about making Lee Sin 
as blind as the borrowed Rek Sai 
, it will make a lot more sense if Lee Sin could persive tremors and having sight restriction with fog of war, than having a blind man, jumping from ward to ward.
Idea: What if he saw the aura/energy of opponents, like Neo when he was in the Matrix, he saw the code, and when he was blinded, he saw their energy in the real world too :O
he would suck so bad lol
but then they'd have to buff him, like buffing the high base damage of his ult, giving it more than 200% bonus AD scaling, and lowering the cd (60 at max rank) of his ult.
Because having seven spells total with high AD scaling, utility, and sustain wasn't enough already.
Rek'sai sacrifices a lot to gain that Tremor Sense. Having it permanently would be so huge a handicap that he'd be unplayable. Tremor Sense is a situational buff, only when you couldn't see the target normally.
I'm sure they could fit it into his kit somehow, but not as a replacement for normal sight (as much as it contradicts him being blind).
( I also just realized he wouldn't even be able to see jungle camps not next to him lol )
i have the same idea but different execution click on link and go down to lee sin rework http://boards.na.leagueoflegends.com/en/search?query=rasalam&content_type=discussion
