For 1, there is a lot of champions that they need to rework. Singed isn't one of them. He fills his niche of being a constant proxy/distraction extremely well, and while he'll never be in worlds, he's still a decent champion. His buff was just a little too strong. I don't see a way they could rework him, and have him still fit his role in the game. He's got a slow, that turns into a root on a flip, which is good for getting rid of someone who tried cutting him off, his poison helps discourage and slow chasers, and his Ult makes it easier for him to get away, if he ever is in dire need of it. His poison trail is also the key of his kit.
2, Cho'gath is eventually going to get a VGU. There is no doubt. But for right now, he was damn near unplayable in draft because he's an easy as fuck counter pick. His Q is the most telegraphed knockup in the game, and his silence is in an odd state. His ulti is perhaps the one thing on him that should never be changed completely, the change they did to it recently made it pretty good. But this buff actually allows him to be played in Draft. That's a good thing.