That sounds like a perfect blend of order and chaos. Start with a clear grid for pathways, then sprinkle beds in a more freeform pattern around it. Use vertical tiers for height variation, and place the most trafficked spots—like a water feature or seating—right on the grid lines so people stay on path. Keep the borders simple, maybe a low stone wall, but let the plants spill over the edges to give that natural feel. You’ll have structure for maintenance, but a garden that still feels like it grew on its own.