During my last "large team run" (Catch at least one of each species, only use Pokemon within five levels of your weakest, no grinding for levels, no buying revives or potions), you really get to learn a lot about shitmon and the game's AI.
You are usually about half the level of trainers, and wild Pokemon can give you a ridiculously hard time when you go to a new route. It's a nice change of pace from the gradual rival ROFLstomp you usually do if you play normally. You really need to use every tool at your disposal.
I did this in Alpha Sapphire, and May's Wailord became an incredible problem since it could just rest a lot of my strategies away. The only thing that I could really do was Encore Lock it, forcing me to level Plusle to the point where I couldn't use it for a while. (It was one of the MVPs)
If you really want the full shitmon experience, you should really give it a shot sometime.
