The shackles are definitely an overreach. I didn't even notice at first that this point was described in detail in the first post (for what reason?). I thought it was a standard repetition from the usual rules regarding the shackles – that there should be a kind of save reload. But it turns out it's much different. An awkward attacker shouldn't have such advantages.
There will also be a catch with the 4th-level mages. That is, any hero will be able to use this magic after learning it... except for the specialist himself.
And finally, add a point about the black market: who should choose the city first.