I think heatran should have a more important role as hes my fave legendary I once even made my own game called pokemon jade with heatran as the star so heatran should be more important if giratina gets to be
The only reason Giratina was boosted popularity-wise is because he has things in common with other legendaries, while Heatran has nothing to do with other legendaries, so Heatran will most likely stay in the same place. But he's still awesome.