I wonder if this is because Fire, Grass, Water, and Electric are probably the four best known types. Three of those have starters, so the fourth gets a regular gym slot. Plus it helps the whole "starter choice=difficulty" thing in the earlier games; grass does well, fire is neutral, water will struggle. Oh yeah, Pokemon idea, I want a circular Pokemon with a 31/41/59/26/53/58 stat spread, with the evo having 62/83/18/53/71/79 . Competitive viability be damned! Personally I took an instant dislike to Haxorus when my Fraxure evolved. Its proportions just look awkward. Like Salamence (who's a fatass), it's a Pokemon as ugly as it is powerful. And having a Hydreigon will just get you teased when you say its name and the other kids say you're pronouncing it wrong.