Games with a dominant Earth drake will have less damage, but it has the potential to be one-sided. If your team takes all the Earth drakes and get the soul, you are significantly tankier than the enemy.
Even if you both take the same number of Earth drakes, its effectiveness depends on your comp. A team full of assassins, burst mages, and marksmen will not get the same amount of value as a team with bruisers, battlemages, and tanks. Lots of champions have abilities that scale with armor and magic resist, and some runes do as well.
This is why it's so important for us to know what the dominant drake will be before the game starts, so we can plan our champ and build accordingly. If I know that the enemy could be getting free armor, then I might choose to play a champion that can reduce or ignore it, or avoid playing champions that can't deal with armor, or ban champions I know will get a huge benefit from it.