The E change has been a long time asked-for. It actually shreds almost the same amount of armour, if not more, on everyone with pretty much one finished armour item. Which now includes Marksmen since the GA is pretty darn good on them. Under that, well, their armour is so low it doesn't matter much either way. I think the break-even point was roughly 114 armour? Easily achievable. I will admit that I didn't expect them to have it as high as 35% though, when it was mentioned that they were investigating changes.
His ult change is really interesting. I'm surprised they're trying something like this. It makes using his ult a pretty HUGE spike in effective power, nearly, but not quite, doubling his damage output. He's gonna be even more of a terror when splitpushing. (With triforce alone you can get off 2 autoattacks between Q cd at max CDR. 1 autoattack when his ult is active at max CDR. Still a considerable damage amplification.)
He can still be kited via movement abilities and hard CC so it's really giving him more ability to do damage when he actually IS close enough to someone before they slip away. Or die. Then he can clear the nearby minion wave faster.
His issues in contributing to full-on teamfights still exist though, maybe a bit less than before since his Spirit Fire does more to their frontline. I believe they really should. He does need weaknesses outside of taking time to ramp up damage on Siphoning Strike.
Still, though, I am likewise ever so slightly worried that they'll take out power from the rest of his kit to compensate, if he spikes hard in win rates. I'm not gonna try to predict what they're going to do since I've been patently wrong on far too many occasions!
I'm just gonna wait it out and see what they do. If the changes actually are a HUGE problem they'll hit him with a hotfix like they're doing with Singed. They've been doing decent recently. I'm a lot more happy with how balancing is going than I was over a good part of the last year, hahah.