The Japanese Street Fighter IV player Iyo has finished first in a recent national tournament, using Dhalsim.
This tournament had some of the best players in Japan, including the legendary Daigo Umehara who didn't even place in the top 8.
Here's a clip of the finals match between Iyo and the Sagat player RF.
While some people like to put a lot of faith in the tier rankings, things change and the rankings are only a general idea of how the characters stack up against each other.
They cannot ever take into account your own personal level of skill and strategies you bring to the table.
I think a Dhalsim player winning a very prestigious tournament proves that.
Thanks to the SRK user Ohayo1234 for this information.