Also yes, I think all the cheating scenarios, that people came up with here, are way overblown. I don't think any evil, massively executed plots would be realized. As BB-Marin stated, it would be harder to cheat with second teams.
For example, the draft sabotage thing? Really, say 300 Greek managers(THE SPARTANS), creating secondary teams in say Poland, ruining top draft prospects? First off, unlikely, second, how about BBs introducing a simple one-sentence rule: "It is forbidden to abuse the second team option". GMs will ban anyone who is breaking this rule.
Marin said it will be harder to cheat, simply because both of you teams get banned in case of illegal operations, so people won't risk their main accounts. For example, it's way easier to create multiple accounts in your country, and then buy and ruin the top draft picks off the transfer list.
Two nations training players for each other? You can do that now, by creating a farm team.
Bottom line, and BBs and GMs will support my statement, is that cheating will always be possible. And it will be dealt with. Second teams won't cause an anarchy.