Then why hasn't Federer won Roland Garros yet?
Like Vlakto said..he has a lot of time.Federer's game on clay is only slightly less effective than his game on other surfaces.He has reached 3 consecutive French Open finals.He would have won all 3 had he not faced a clay court monster like Nadal.Sampras only had one French Open semifinal to his name,and he would get owned by much lesser players on clay.Both are great players,but Federer has done well on all surfaces,unlike Sampras.
No, I don't think so. The difference in class between the current roster of tennis players and past ones is huge. You can't compare the likes of Djokovic, Nadal to Becker, Chang, Edberg, Agassi, Courier, Ivanisevic and the rest of the greats. All those players were in their prime and Sampras was still above them. That was a great achievement. Sampras is possibly the best of all time. I have to admit that and I don't even like the guy.
Chester got it spot on.Whereas i do think that the competition Sampras faced was tougher than what Federer faced,i dont think that the difference is huge.Out of the players you mentioned in your list from Sampras's time,Agassi and Becker are are the only one who qualify as tennis greats.The rest dont.If we're calling Chang,Courier and Ivanisevic greats,then we might call Hewitt,Roddick etc tennis greats too,but we all know they arent ones,just like Chang,Courier and Ivanisevic arent greats.And like Chester's said,the only player amongst the ones you mentioned who saw his peak alongside Sampras was Agassi.Becker's peak was in the late 80's,when Sampras only became professional.Chang only won a single grandslam title,and he was hardly a threat to an onsong Sampras.Courier won his 4 grandslams before Sampras reached his mid 1990's peak,and Ivanisevic,despite being a very lovable player,was too one dimensional to challenge Sampras,let alone be called a Tennis great.Like Chester said,he's a lot like Roddick.Great server,great power,but someone who cannot threaten a truly top quality player.Sampras had other good players in his time too..but only Agassi and Becker can qualfiy as the true greats.It comes down to Agassi alone when you take Becker's late 80's peak years out of the equation.
I know it all sounds like im trying to demean Sampras,but thats not the case.He's a legend of the game,and someone that i respect a lot.But Federer has got all the makings of ending his career as the male greatest player of all time,and im not talking about stats alone here.The difference between Sampras and Federer isnt huge as things currently anyway..and he's only 26.