I multiboxed FFXIV for several months after it came out without issue. As far as I can see there's nothing in the terms of service and there are multiple threads on the Square Enix forum talking about multiboxing. It's a bit annoying when companies don't openly state what the rules are. My guess would be it's fine unless/if you start engaging in behaviors that impact other players.

Since there's no real PvP in this game I doubt people will cry about it as much as they did in WoW.

The game itself is pretty well made. Slower than WoW but there's a good amount of content. I just can't maintain interest in playing something knowing there's no PvP end-game.