No, not dissonant. Dissonance would be going to a chord that is not in the key. Like the tri-tone substitution, ii bII7 I instead of ii V7 I. Even through there are 2 notes (4, 7) in the bII7 and V7 that are the same. 2 notes (b2, b6)are outside the key. Of course this is what makes this sub. so applicable. But it is dissonant.

The change between seconds is just strong. Try it on your guitar (x32010) to (xx0231). C to Dm. That change is strong while (x32010) to (x02210) is weaker. C to Am. If you play it you should see what I mean.