Couple more replays of araquanid:I wouldn't say Araquanid is the most splashable water, since we have other Water-types that are better, such as Milotic, Azumarill and Tapu Fini, that are far more splashable on teams compared to Araquanid.
http://replay.pokemonshowdown.com/gen7doublesou-541784122
http://replay.pokemonshowdown.com/gen7doublesoususpecttest-542265100 (hydro vortex ohko's kang regardless of crit, just fyi)
When I say that I think that araquanid is easier to fit on a team, I mean that unlike milotic, azu and fini, araquanid requires no support to function, and doesnt require set up or for the opponent to be having intimidate. In the above to replays, it puts in a ton of work against two very standard kang and mence teams.
I think the fact that, much like aegislash, it is capable of operating on a fast team as the slow mode TR check that still offers good power, utility and bulk with no support required for itself against non TR teams is what warrents a rise in the rankings.