I didn't mean to suggest you were referring to overstocking. Overstocking represents a gradient, anyway, not a specific point. As you said, less is best. But the problem is that people have bought into this nebulous idea that you can "push the limit" with planted tanks, as you say, and my contention is that when people challenge those limits without the proper experience behind them, they end up creating problems for both the fish and the plants, instead of for just the fish as before. In contrast to what's normally 'taught', I've found that moderation in stocking becomes even more important in a planted tank.