I mean style of play, game-wise, let's not even talk about achievements. Or arguably the best to see of all time vanish after his retirement.
Unless anybody has a crystal ball that actually works, who knows?
For his fans and people who are now able to watch and admire him, he is unique.
People who have watched players like Borg, JMac, etc. still talk about them with fondness.
However, tennis moves on and we will see new and exciting tennis players coming up. Once you've been a huge fan of one player in particular, there's the temptation to keep on comparing every newcomer to your own favorite, thereby risk missing the excitement others bring to the sport because in your eyes, he's just not that one player you admire.
So, we won't have another Federer (he's not gone yet, he may even have a number of big titles in him yet) but we will have other great and exciting players.
I haven't seen anything quite as much off the deep end as this.
You don't visit GM often, I take it.