The lack of young players emerging and making significant waves on the ATP tour is incredibly worrying and has already been commented on. In previous eras when I attended tennis tournaments, I also liked to look out for exciting young rising stars. Other than Wimbledon I don't have the time to attend other tournaments nowadays, but still it's very slim pickings in the rising stars department. To me that's just boring. The worry thing isn't necessary the inability of the younger players to challenge Federer or the Nadal, but the fact that has taken so long for them to even overtake the second tier of players that were born in the early to mid 80s.
I am British, but I also don't like the insane European domination of men's tennis. In theory the range of nationalities of the top players shouldn't matter, but in reality it kind of does, and I would prefer to see a greater geographical spread in that department.
The last 31 grand slams (i.e. every single slam this so far this decade), and 52 out of the last 53 dating back to Gaudio’s 2004 RG triumph, have been won by European players. Of course that one exception was Del Potro’s 2009 US Open title.
The last 66 masters series events, and 85 out of the last 86 dating back to Nalbandian’s back to back titles at Madrid and Paris in 2007, have been won by European players. That one exception was Roddick’s Miami title in 2010.
So far this decade, 107 of the 108 ‘big’ tournaments (that includes the grand slams, the Olympics, the YEC and masters series events) have been won by European players, including all 31 grand slam events. Again the sole exception was Roddick's 2010 Miami title which right at the start of the decade, which means that the last 105 big tournaments (and counting) have all been won by European players. It looks pretty likely that there could be a total European clean-sweep of the men's grand slams in the 2010-2019 decade.
1997-2002 was certainly a golden era in the geographical diversity department, especially 2001 when all 4 male grand slam champions were from different continents; Agassi, Kuerten, Ivanisevic and Hewitt.