all games have alts. I don't think there is one game where people do not have alts. In WOW I had an alt follow my main to duo instances, Everquest i had a powerful healer alt to heal my main, in Diablo I had alts galore, goes on and on.

Alt is not the issue.

Trading increases the game fun factor and gets players more engaged. It is what can make a game "more addictive".

Having an alt can go both ways so at the end it all balances out.

But being able to trade has more positive than negative.

I'd love to sell my blue stars to people who are struggling and have been struggling for many months.

Sell hard to get plans like relic plans, etc.

Once item is crafted it can become account bound. The possibility is endless on how it can be implemented.

But one thing for sure, there would be a lot of people on the trading forum.