This is a hypothetical scenario where level 80 kyogre is allowed but only 1 drizzler per team --- Official Keldeo of the Pokemon Black/White 2 boards. I frequently use a tablet so excuse my spelling/grammer.
At L 80, Kyogre will have fairly more SpA, slightly more SpD, but slightly less Speed, Defense, and much less HP than Politoed. Kyogre has a better offensive movepool with Water Spout and Thunder.
However, keep in mind that due to the way the damage formula works, being at L80 means that the part of the formula that uses level as a factor will have a multiplier of x34, rather than the x42 multiplier that Pokemon at L100 have.
This means that even though this L80 Kyogre still has a good SpA stat, it will be doing 19% less damage than a L100 pokemon with the same SpA stat. Because of this, Politoed technically has more special attacking power when the math is done.
I'd say Politoed is much better stat wise, unless you really want Thunder and Water Spout.
Similarly, Toed is only slightly bulkier. Kyogre, on the other hand, has a much better movepool, which really is the deciding factor in this case. --- I claim to be the official Porygon2 of the Pokemon Black 2 board. Scientist MileRun: WaRy associate