Poor Sonic... BThrow getting a nerf really hurts Sonic's game. I was using it and it didn't kill until FThrow %'s (staled it a bit trying to kill them with it though).
Think of it this way:
You now need to land approximately 50% more SD/SC as you did before to get them to the OLD KO % for your Throws. Now you need to land... wait for it... nearly DOUBLE the SD/SC as you did for the NEW KO %. Obviously there's a lot of variation with SD/SC damage depending on where you hit them, which aerial you can connect if any at all, etc. However, this means that Sonic needs to work roughly twice as hard for his BThrow KO's.
Compared to Diddy who can still do ~30% DThrow Combos and bring you to 46% in 2 Throws, Diddy only needs to land 1-2 extra throws or bananas to KO you (although no more Hoo Haa kills).
Sheik was nerfed (BAir damage/knockback) but damage output still the same (needs to land about 2 more attacks to bring opponents to the new KO %). Pikachu was pretty much untouched. ZSS and Rosalina were untouched.
I'm sorry but I don't see Sonic even being in A tier anymore. IMO he will be the top of B Tier. Sonic was a medium risk high reward character. Now he's a medium risk, medium reward character. He was nerfed the hardest along with Diddy. He now needs to land twice as many SD/SC as he used to and against good players, it will be twice as difficult. Obviously you can still FSmash, YOLO Up Smash, and BAir before 140% to net the KO, but good opponents will rarely get wrecked by these options (except a good air read BAir, but characters like Sheik have far too many recovery options for you to consistently pull the read off) and you may get punished really hard for these options.