Not gonna lie, stratos probably wouldn't even be that powerful. His backrow removal is nothing gamebreaking, especially when it requires you to already have other heroes on the field, and duel links doesn't really have the tools to abuse his searches to the fullest.
Stratos isn't even broken in the TCG and its ban has become so ridiculous to the point where it has become a meme. Don't use it being banned as a reason it shouldn't be in Duel Links. It probably would be just fine.