You can watch Federer 19 years against Sampras at Wimbledon . Federer has such a variety in his game.
federer doesn't play like that anymore
yes, he could have been the love child of sampras, edberg and lendl in a three-way, but that's not how things happened
nowadays, he looks aggressive because he's surrounded by defensive players, because he goes to the net occasionally, and in this slow court era, uses variety