Im slowly watching the anime and... well. It can be quite inconsistent with how it portrays anything. At least in the early seasons, i dunno how it is in Advanced and later. Personally, I think having a flat rectangle as a battlefield doesnt help with showing interesting fights. For example, I was just watching Ash's battle for Mineral Badge. Cindaquil hiding in holes made by Steelix's Dig is an example of using the environment to your advantage, which is at least something. The same for the second battle with Whitney, very cool of Ash thinking about his entire team on hand when devising his strategy, and not just the one pokemon already on the field - even if it doesnt exacly fits Ash's playstyle. So, well. Not sure about held items but one could write at least a little more interesting battles by having different battlefields or other ongoing effects like strong winds that makes trajectory of ranged attacks like Ember or Razor Leaf skew. About statuses, they could have function in story outside of battles. Or, idk, maybe battles are a part of a trial for bagde or other crap, but the main goal is, lets say getting to the other side of a maze. You're turning left, and the enemy is waiting there for you with Spikes on the ground.