Asked by Batata 2126 on Twitter
Per pure Max CP values, these Pokémon are the highest ranking in Generation 3. Do note that we expect Slaking to change, as 5k+ Max CP is just… insane.
Other notable entries include Metagross and Salamence, due to their crazy high Max CP that is considered to be meta changing.
We are disappointed in Aggron and Armaldo, but they’re still fairly high. Walrein is also a disappointment, but still not bad as Blaziken. Remember that these results are preliminary, much can change once Gen 3 actually releases.
We will be updating this answer when more accurate information becomes available, for now we’re basing it on base stats from the main handheld games.