I have an idea then might help the infamous knife cat

So, as I'm sure most of you are aware, Rengar is in a pretty bad spot despite the changes to his passive, Q and R. With that said, I feel as if one of Rengar's biggest problems is actually his W. This whole time everybody's been talking about his other abilities (most notably his Q), but what about this RAAAWR button? Well, for starters, let's compare his old W to his new W:

Old W: Rengar screams really loud to get bonus resistances, up to 30 with the amount being increased by 50% for each enemy champion and large/epic monster hit, and the empowered version healing him based on his missing health. This was perfect for him because he could get a stack of ferocity AND resistances. Or in other words, he was rewarded for threading his W into his combos, and in emergencies, he would get a pretty big heal to give him just enough to escape.

New W: When Rengar receives a nasty boo-boo, he screams the pain away, healing for 50% of the damage he has recently taken, increased to 50% vs monsters. When empowered, Rengar cleanses any CC on him. This is... not so great, because while it may work decently for bruiser Rengar, is just doesn't do the job for lethality and crit Rengar. They're so squishy that often times they will die before they even get the chance to heal. Not to mention this W forces the player to either use his W for the heal or for an immediate stack, but never both, thus basically forcing players to go bruiser in order to have any kind of success on him.

My profession! Uh, I mean, proposition: Change his W so that it will grant Rengar a shield that scales with his bonus AD rather than a heal upon him taking damage. This way, he doesn't get punished for using his W the way he ought to, his jungle clear will be healthier, and he doesn't get bonus Armor and MR either, which for an assassin/diver just doesn't make any bit of sense.