Problem is -- 10 or 15 years ago is not 2004-2007.
Hewitt began to falter after 2002 when he lost some of his foot speed. Nalbadian although extremely talented, never got his fitness level up to where he could consistently challenge the top players. The only player who was consistently in their prime when Federer started to dominate is Roddick. And I'm sorry but Roddick's prime form is too one dimensional and just does not compare. Roddick never developed a decent transition game. Roddick's ascendency to #1 and perennial presence in the top 8 speaks even more to the relatively transitional time period of 2004-2007.
Again, not weak just weaker than now...
OK, now I know why we disagree so much. It's um...Because you don't seem to remember this time frame very well.
Hewitt 2004: R16 at AO, lost to Federer (eventual Champ), QF at French Open, lost to Gaudio (eventual Champ), QF at Wimbledon, lost to Federer (eventual champ), Finalist at USO, lost to Fed. Finalist at Tennis Masters Cup, won 4 tournaments that year, and made 3 finals.
Hewitt 2005: Finalist at AO, lost to Safin, Semis at Wimbledon, lost to Federer (eventual Champ), Semis at USO, lost to Federer (eventual Champ).
Just for Hewitt alone, he went 7 straight Majors where he lost to the eventual champion. Sure, he didn't win a slam in that time, but he made 2 slam finals, 2 semis and 2 quarters...
Safin made the 2004 AO final, won 2 masters tournaments that year, and made the semis of the Masters cup. In 2005 he won the AO.
Nalby in 2004: QF at AO (lost to Fed), Semis at the French (lost to Gaudio), he was a finalist in Madrid, Rome, and Basel.
Nalby in 2005: QF at AO (lost to Hewitt 10-8 in the 5th), QF at Wimbledon (lost to Thomas Johannson), QF at US Open, won 2 titles including the Tennis Masters Cup.
I mean...I can go on. Roddick obviously has a great resume in those two years as well, not to mention at Agassi was still making deep runs and Nadal burst on the scene in 2005. People tend to seriously underestimate that time frame, even going to the lengths to say Hewitt, Safin, Nalby, Roddick etc. didn't do anything or were wildly inconsistent.
Clearly that's not the case, and again, I just mentioned four guys above, that doesn't include other great players in that time frame (like Federer, Gaudio, Ferrero, Agassi).
Also, you seem to act like Roddick was #1 from 2004-2007, or that his presence in the top 10 was unwarranted. Roddick was #1 at the end of 2003 and for the first bit of 2004, until Federer went on a tear. In 2004 Roddick was #2-#3, and in 2005, Nadal took over as a permanent #2, and stayed there well through 2007-2008. You also seriously underestimate Roddick's abilities, and I think that's backed up by the fact that a past prime Roddick has a 5-3 h2h with Djokovic, and even beat Murray at Wimby 2009 in the semis, when most thought that was Murray's best chance at a slam. Roddick was also in the top 10 for 10 consecutive years, up until 2011, THREE full years into what you're calling the stronger era. Yet there was Roddick, past his prime, and still in the top 10.