As Auld Jag has already noted on another thread, Tommy experienced a Damascus Road conversion and saw the light at half-time of the Celtic cup tie. He followed a dreadful first half with a creditable second half, and then took that confidence into the next few games (especially against Dundee United where his skilful movement won the penalty).
I agree, however, that this was a case of "too little" and certainly "too late", and his departure is hardly a cause for wailing and gnashing of teeth.
Lady Isobel Barnett has also commented on his lack of versatility. This is surprising. You would have thought that with a name like Tom Robson, he would be equally at home at Number 2, 4, 6 or 8, and that he would always arrive on time.