To find the most competitive league, I'm going to use Standard Deviation, a statistical measure of spread. It finds the spread from the mean; the lower the Standard Deviation, the more competitive league. I'll then rank each league in Standard Deviation and goals/game, add the ranks together, and divide by 2. For example, a league that ranks 15th in competitiveness, and 10th in goals/game will have a rank of 12.5 (15+10=25/2=12.5).
First up is South America, with 10 leagues.
The Data is here, but I'll put it below.
The best league in South America, in terms of excitement is Boliva; first in competitiveness, first in goals/game, it's the most exciting, though maybe not the best quality. The worst league, in terms of excitement, is the Paraguayan league, which has the second least goals, and lowest competitive ranking.
Next up: Oceania