It doesn't seem like that's the plan right now though. Ideally they'll offer Solo Self Found seasons that bar all trading, and offer regular open trading seasons for others.

The question is how much do they want to limit people who don't engage in that activity? No matter what Blizzard do, whether it be limiting trading or having absolutely free trading there will still be people spending their 'Forum Gold' or using other real money sites to buy things in the game. The real money transaction side is an unfortunate side effect. With seasons coming from the very start they'll be able to continually curb inflation by resetting the economy every season. There's a certain joy as an active trader when you get an amazing drop that you can't use, but you know it's valuable and can be traded for items you need, or currency to get items you need. An economy adds longevity to the game by adding a whole new layer for interested players to explore.

It shouldn't be a requirement to engage in trading, but I absolutely think it needs to be there. The fact is for a lot of people using trade chat and trading is playing the game. I see where you're coming from, but I'd rather have open trading.