I don't think Witsel has done anything wrong really. It looks like he always fancied a move to Italy which is his prerogative, but no team in that country at the time matched either his clubs asking price or his own personal terms. If as reported, Inter have now done that, fair dues he gets his first choice move. His agents were doing their job well for him in having us as the fallback option.
However, like any other supporter, it feels like he has messed us around and/or we have been used by his agents - but in reality would we be any different in obtaining the job we really want?
It is only a problem if we missed out on other targets waiting for him to make his mind up, which hopefully we haven't and are players who would see us as their first choice.