I think this is the era where Ireland have the most relevance in the world of Rugby, through the scope of players, individually. When I made this thread, I was thinking "ok we don't need Kearney, Dulin's good enough. Oh yeah, they've got SOB...oh wait, I think I want Healy more right now, yeah...oh and Sexton, he's def. one of the Top 3/Top 5 right now...and Stephen Ferris just retired recently, I'd have taken him also...Best is also a very good hooker...heck even Mike Ross may be a more stable commodity in the front row under the new rules..." - (I picked Healy).
And there's still Connor Murray, recognized as one of the best 9's, then there's a POM or an iconic Paul O'Connell. I'm not just merely name-dropping, those are worthy names to bring up. Jamie Heaslip, another big name, and D'Arcy but I don't rate him very very high, personally.
About flyhalves in the world right now, I've said it before but it's a position that requires so many different things nowadays (defense, tactical kicking, kicking from tee, passes, attacking), it's hard to find the one guy who does it all well AND has a little bit of that magic, that little extra that helps you pick the one player for sure.
Sexton "does everything" but lacks the little extra that an on-form Michalak still brings, or Cruden or FTD. Cruden has some magic and does many things well, but then he's too small and that's necessarily a flaw, and his kicking at the posts looks a little meh (wtvr the stats % say). Plus he drinks, (that little fkr...).
FTD probably just suffers from no international spotlight right now, nothing else; and the Coopers or Michalaks (milkshakes) are inconsistency Supreme, well Cooper looked very good last time we saw him.
The other popular 10's: Plisson very good but too young/too perfectible, Owen Farrell very solid and underrated but too one-dimensional, Foley is really good but he's not incredible, Pollard we need to see much more, Dan Carter always injured or playing another position lately, Beauden Barrett very good prospect but not the best in the world, Nicolas Sanchez very good in everything really but again not THE best, Morné Steyn nahh...there's also Giteau (whom everybody sees as a center) is clearly one of the best in the Top 14, therefor in Europe, and in the world..but THE best ? Jonny's gone...
So see, it's really not clear-cut and I do think without being reductive that Sexton benefits from striving in an era that is a little bit soft with its flyhalves. There isn't a resounding answer to the question really..like if I say OS flanker, everybody's thinking MICHAEL HOOPER !! An SOB comes to mind too, Alberts...