Vayne early game buff, late game nerf

I'm not particularly saying she NEEDS one, but I was just thinking about it. She's a hyper carry and, like all hyper carries, they get pretty annoying once they get a kill and just take off and are unmanageable as the game goes on. So here's my thoughts: 1.) We make Vayne's Q a static 4 second cooldown and increase the mana consumption to a static 50-70. 2.) We move Vayne's percent health damage onto her Q and make it a physical 2/4/6/8/10%. 3.) Revamp W into something like a Draven W or increase her life steal for a short period (2-3 seconds, 10% lifesteal?) with like a 15-20 second cooldown. 4.) Maybe extend her ult duration to 9/11.5/14 seconds to allow time for decisive tumbles (you get more time with ranks)

It would give her a little more pressure in the early game to tumble in for a quick trade, but she can't do it too often or too much or she'll go oom. And it will eliminate the 3 autos making it a little easier to get her damage off and it won't be ruined by a taunt, misclick, bug, or whatever. Also, to make up for the more reliability, the CD is higher at late game and you can actually build against it. The change to W would give her a little bit better of chances of survival in between tumbles when she goes stealthed or if the enemy has pink wards/scanners ready. (She can counterplay her counterplay... kind of like how tanks get thornmail) Since the tumble is a longer cooldown late game and shorter cooldown early Vayne will instead be allowed to tumble twice for her first two levels of her ult and three times for her last level. Whereas she can only currently, if you're maxing Q, tumble 2 twice JUST BARELY on the first level. But most people now max W still (from what I've seen), so Vayne can only tumble generally 1-2 times during her first two levels of her ultimate. And it's a little obnoxius that she can go invisible up to SIX TIMES at end game.

Like I said, I don't really think she NEEDS this change per say... but I also don't think it would be a terrible idea.

P.S. If you're wonder about her E, it's just an unreliable stun/gap maker. It's kind of like a better Popppy E.