What has changed is that newer 2-strokes are making a lot more power. Water cooled marine 2-strokes should use a BIAA or NMMA TC-W3 rated oil. Air-cooled 2-strokes (chainsaws, motorcycles, snowmobiles, etc.) should use an API TC rated oil. If you really want to use just one 2-stroke oil go with NMMA TC-W3 TM. The TM designation indicates that the oil is approved for both water-cooled and air-cooled engines. Typically, a water-cooled type oil will be a heavier oil with low detergents, and other additives to prevent rusting and provide anti-oxidant protection. The air-cooled oil will be a lighter oil with higher detergents. The API TC oil costs more to make.
I'd say that if you're running an old water-cooled outboard than the oil isn't that critical, but if it's a high-performance air-cooled 2-stroke, like a modern chainsaw, then the API-TC is a must. My Stihl Pro 361 chainsaw makes 4.4 hp and spins at 13,200 rpm; it needs a TC rated oil.