I think he's quite promising. At 16 he was one of the brightest prospects we'd have over the last 4-5 years. He was scoring lots of goals for the under 23's (and was given game time for them as an under 16 which is rare). Lots of talk that summer that clubs such as Arsenal were looking to pounce.
Unfortunately for Antony that was sort of the pinnacle of his time at Everton. He seemed to have some issues with growing, he went from being a 5 ft 10/11 16 year old who looked powerful and in control of his body, to a lad who's probably 6 ft 1 but a little gangly. In truth he still looks a little gangly to me but is a lot better than what he was 18 months ago. He probably needs to "fill out" into his body and get more confidence from it.
He got moved away from his number 10 position, and would play a lot off the right and left, which again I don't think massively suited him. They put him out on loan last season to (league 1 (Third tier) Crawley and he didn't get much game time there.
In truth, there have been issues with how we've developed a lot of players between the ages of 16-21 and he is probably the best example of it. There is some criticism levelled at the under 21's manager (that he is too conservative in giving younger guys game time) and changing managers, scouts, DOF's so frequently (all with quite different styles) has not really helped either. That being said, the lad just doesn't look to have kicked on much in the last 5 years which is a shame.
The positive for you though, may well be that at 16 he looked a very promising player. If you can get him back to that level, with confidence coming back, and he can bulk out he could do very well in the Bundesliga. He is tall, works hard, good creativity and can get on the end of things to score goals.
I wish him well. Could be an astute buy. Do pop by every now and then and keep us updated with how he is progressing.