Wex: I decided to test out how Animate Weapon currently handles a full field. I assumed it wouldn't allow you to cast. Instead, the game bugs: Doesn't dispose Animate Weapon after notifying that field is full, but does destroy weapon. Except I think the Animate Weapon is suppose to be disposed because using a card beneath the Animate Weapon uses the card but removes the Animate Weapon instead of the card. Trying to use the Animate Weapon repeats that the field is full and stays in hand. I can't conceive how to fill the weapon slot without losing the AM. Have not experimented with Mindgate (I believe that either the Animate Weapon will be overwritten, or the Mindgated card will become the card disposed when duping)
edit Mindgated cards can be played, last card of hand isn't overwritten
In the case of Animate Weapon being applicable to the opponent, it would likely be best to have it not destroy weapons when creature slots are unavailable