^ I've never trained my guys like that, they're usually all within 2 levels of each other, depending on if i'm going through a cave or something similar.

I haven't really made much progress but I've noticed a few flaws with my party. 3/4 of them are KO'd by a ground attack, 3/4 of them are killed by a fire attack, and none of them can really damage a poison/grass type opponent. When your entire party is trolled by a Foongus you know you have issues.

Servine (soon to be serperior) does literaly no damage to anything that resists grass, due to tackle being it's only non grass type attack. Lucario's highest damaging attack does 50 damage, but it can't be poisoned which is a plus. Magneton doesn't do too bad (thank Game Freak for the updated Sturdy ability) and Tri-Attack means it isn't completely walled by an electric type. And finally Trapinch (one level away from evolving) has all the defenses of a leaf. But seeing as its speed is worse than abysmal, giving it a macho brace to hold, which halves it's speed but boosts it's stat gain when it levels up, has no real affect in battle. One level away and it'l evolve into vibrava, become dragon type and best of all learn Fly, so it'l all be worth it in the end.