So if we're willing to make Alakazam A-Rank, what do people think of A-Rank Reuniclus too?
Both Reuniclus and Alakazam are hard-hitting Psyhcic-types who are impervious to indirect damage, and both of them use largely the same moves (Psychic/Shadow Ball/Focus Blast/Other). Alakazam has a higher base Special Attack than Reuniclus, but Reuniclus' tend to run SpA boosting natures, which gives it the edge over Alakazam's who run Timid natures (which they should be).
But while Alakazam is a fantastic revenge-killer and all-around powerhouse, Reuniclus is just a total monster to offensive teams, which let's be honest here, compromise most of the metagame. Since the OU metagame has become a series of Pokemon desperately trying to one-up each other for more Speed, Reuniclus punishes that team focus with it's TR set (it's only good one), and proceeds to massacre everything. Seriously, I mean everything. Get a bit of prior damage on the opponents team, and there's nothing stopping Reuniclus from sweeping, bar an unfortunate Focus Blast miss (which Alakazam has to deal with as well).
Bland typing, predictability, and issues with SpD Jirachi aside aside, Reuniclus is here to ruin lives, and he does that job with admirable gusto.
Reuniclus for A-Rank.