>>37162258Groudon wasn't top of Ubers until Gen 6, and for obvious reasons. Kyogre was king of Ubers, along with Darkrai, up until OR/AS with Primals. Groudon was bouncing between C-tier viability and low A-tier, and fell hard in Gen 6 with the weather nerfs before he got Primal Reversion.
There were points in time when Heatran was higher ranked than Groudon in Ubers viability rankings. Hell, currently Heatran in Gen 4 Ubers sits in A-tier, with Groudon, and ahead of several forms of Arceus, and Pokemon like Lugia and Ho-oh.
Again, you don't know what you're talking about if you think HEATRAN of all Pokemon is all that much weaker than Groudon (without accounting for primal forms). Heatran is a fucking menace.