Amra, you need to really calm down because you honestly seem to be offended with anyone questioning your thoughts on tier lists
Tier lists are subjective in the end because of the experience people has with each character. Suwako is considered low tier because she's really hard to use and hasn't been explored to its full potential, while Sakuya is pretty easy to use (in my own experience) so a lot of people tend to stick with her over others.
You can ask the American community whatever they want, but that doesn't represent the Japanese community and how they play the game itself. Let's take Thor fro MvC3 as an example. Here they think he's a pretty damn low tier character with just high health. But if you see the Japanese community a lot of them USE Thor as think of him as a pretty good character. The Japanese mentality of fighting games are pretty different from the American view. And remember when Vergil was thought to be only okay at first when the game first came out? Japan ALREADY knew Vergil was top tier at the start, and it took the West a few months before they realized this (when they went with Wesker first, then Zero, then Spencer, and finally Vergil).
Sure I can definitely agree with Sakuya being top tier for sure. She's really simple to use, but this does NOT take away from the fact that Suwako is terrible and an unplayable character against her. AGEOJOE was a great example of use low tier characters (and Frank West) and winning AN ENTIRE MAJOR TOURNAMENT WITH THEM because they all thought they were low tier.
Even Hsien-ko is still pretty good. She has one of the best assists in the game with her super armor hyper. Seriously, it's so broken :V And Phoenix Wright is good too, look at Lythero and his videos with him. He just takes a lot of time to learn, but he can kill almost every character with one combo in turnabout mode.
Anyways ENOUGH about tier lists okay? This kind of stuff is what brings players apart and discourages players to ever TOUCH other potential characters and be good with them, and encourages "over-saturation" (aka Wesker over-saturation when in the end everyone knew how to counter him). Just let people be, tier lists are just subjective that a lot of people feel are good because of their own personal experience. You just need to put them to their full potential and I would believe Suwako hasn't been explored too much yet because of this. I believe to ignore tier lists entirely and just play my characters (which is why I play Reimu or Suika main :V)
EDIT: Oh yeah, remember when pre-2012 Yun (who was ridiculously "top tier") won EVO 2011?
Neither did I