I think you're overlooking one very important factor: dominance. Yes, winning 3 slams on 3 surfaces is.. nice, but, ultimately, you're just winning 3 slams. Now, were Nadal to win AO for a NCYGS, that would really be something special, otherwise, no, I don't think the players would consider it particularly spectacular. On the other hand, what McEnroe displayed in '84, what Federer displayed (particularly in '05 and '06, '04 and '07 were clearly lesser years in my opinion, in quality if not achievement) was absolute peerless dominance, the likes of which haven't been seen since Laver either. Nadal hasn't come close to subjugating the men's tour like these two did.
So yeah, Federer's '07 I can easily see the argument for, but to consider it the best tennis year since Laver's '69 is an absolute mammoth stretch.
While winning a NCYGS would be quite an accomplishment, the thread is about calendar year accomplishments...
To me, the whole "dominance" argument sounds like a fan's perspective, not a player's perspective. If your opinion is that the players care about being dominant more than winning slams, or that dominance would break a tie in slam titles, I have no problem with that opinion. I just disagree. Even the great ones can have a surface that gives them trouble. You think Mac would have traded a few victories in '84 for a FO title? I do. As Fed was being hammered by Nadal in the 2008 FO final, if he magically had the opportunity to trade some previous "dominance" for a single FO title, do you think he would have done so? I do.
Again, all bets are off when you consider a career. If you know you are going to win every major event anyway, or feel confident about your chances, then perhaps it just doesn't matter?
As for the "mammoth stretch" part, I don't know what to tell you. Nobody pulled off what Nadal did since Laver, regardless of how "dominant" they might have been. And nobody did the FO, WIM, USO triple on three different surfaces. If that doesn't merit consideration for top season in your book, that's fine, but I think the accomplishment speaks for itself. Everyone is free to have their own interpretation of accomplishments, and I have no interest in changing anyone's mind on this topic. The OP asked for opinions, and I've given mine.