I really don't think so. My valuation -- and I think most others too -- has nothing to do with that first goal. It is rather based on his play for us (where his talent has definitely been apparent), his performances during the u-20 World Cup, and, especially, his terrific play in Germany.
I don't think he is "only potential right now." He is not a player being called up from the U-18s. He has proved himself -- first at the lower levels and then in the Bundesliga. His performances in Germany, in particular, have moved him beyond "potential only." Just look how bad Liepzig want him.
Not having a pop at you, I'm agreeing with most of what you say, just putting some reality in the mix.
In one and a half seasons, as a 17 year old, he made 45 appearances and scored 10 goals for Charlton in both the Championship and League One. So yes, he certainly had it in the lower leagues.
He came to us for 7.5m rising to 11m with add ons and he stayed for 12 months.
He made 24 appearances for the first team in all competitions, totalling 809 minutes, and scored 3 goals. One against City on his debut and two against Apollon in the EPL. (Scored in 2 out of 24 games) so not exactly setting the place on fire, but that could be down to the managers.
Under Unsworth he also made 3 appearances for the U23 team, totalling 220 minutes and also scored 3 goals. So he can also produce the goods at Under 23 level and under a different manager.
He then went to Leipzig and made 11 appearances, totalling 575 minutes scoring 5 goals and 3 assists. These goals were against teams in the lower half of the Bundisliga, 2 against Wolfsburg who were relegated. He never played against your Bayern Munich or Schalke or Dortmund so we can't say how he would have performed against the best teams in Germany. But against lower opposition he can certainly produce the goods.
I don't think he is in Silva's first 11 plans, whereas if he goes to Germany he'll probably start each week. He's young, probably headstrong, (he dug the heels in about going to Derby), he more that likely wants to just play regular football. I don't think he is buying into the wonderful Brands/Siva project and the fact he remained on the bench against Bury was significant. I think he will go. It would be a bit ironical of Marco to force him to stay after his Watford scenario.
Just a thought if he does go for 20m euro do Charlton get a cut?