I'm a fan of this topic, although I will say that after having brought Cinccino (Rascal <3) into OU on more than a couple of occasions, lower-tier threats are very viable in OU. You're absolutely right when you say that there are other similar Pokemon who do the same thing better; after all, Cinccino is always beaten by Ambipom and Cloyster's bulk and access to Shell Smash makes it a much more viable Skill Link user. However, let's not discount the unpredictability of a lower-tier Pokemon; I cannot count how many times my team has been completely walled by Quagsire, thus forcing me to run something with access to a powerful Grass-type move (like Cinccino's Bullet Seed). Furthermore, I would have used Dragon Dance Whiscash as the example, as the attacking set (Waterfall and Earthquake) is the same, but with STAB.
Tony is absolutely correct when he says that some things will never be viable. Sorry Pachirisu, but you will NEVER find a spot on an OU team where you do anything right aside from look kawaii as fuck. I also think he's right when he says that we need to stop using such unoriginal Pokemon as Blaziken and Excadrill simply because they're a nearly guaranteed sweep. I just want justice for Rascal the lower tiered Pokemon we all love.