My personal tier list for SFV Season 2.5 (at this current moment). This is all my own opinion so feel free to disagree.
S Tier – Ibuki, Karin, Cammy, Necalli, Rashid
A Tier – Guile, Akuma, Laura, Balrog, M. Bison, Urien, Zangief, Ken, Chun Li, Kolin, R. Mika, Dhalsim
B Tier – Ryu, Juri, Nash, Ed, Vega, Birdie, F.A.N.G, Alex (I personally think Alex is the weakest character in SFV which is why he gets his own section)
S Tier – This character is one of the most well-rounded characters in the game. They have everything you need to be a good SFV character: 3F normal, invincible reversal, easy comeback factor, amazing ground game + antiairs, etc.
A Tier – This character is strong but lacks something that would put them in S tier. This character is still capable of winning a major tournament if played well.
B Tier – This character is decent. If played by a very strong player, they have a chance at winning a major tournament. However, this character has one too many problems when compared to the S/A tier characters.
Why are there only 3 tier levels?
SFV is fairly balanced at this point. There aren’t many overwhelming matchups in the game at the moment (i.e. 7-3 or worse matchups) and due to the nature of SFV, it’s possible for any character in the roster to do well in a tournament. For these reasons, I would never count out any character in SFV. It’s easy to snowball/make a comeback in a match and win with any SFV character. Never give up!