I don't think so, and the reason is that Ezra ha Sofer had made a decree that men cannot learn until they go to the mikveh (to try to get them to have relations less often.) Later it had to be rescinded, but the fact that they made the decree shows that there is no per se mitzvah to go to the mikveh.
But you should go to the mikveh if mashiach comes and you want to be ritually pure :D
Also, I seem to remember the sefer Kav HaYashar, by Rabbi Kaidanover, explain that the impurity of the keri does attach to your body and makes it harder for you somehow. It's a good book, if scary, check it out.