I think if you look at the somewhat recent history, you'd come up on top more often than not taking #1, instead of #2 and #4.
Who would you rather take:
2012: Anthony Davis or MKG and Waiters
2011: Kyrie Irving or Derrick Williams and Tristan Thompson
2010: John Wall or Evan Turner and Wesley Johnson
2009: Blake Griffin or Thabeet and Tyreke Evans
2008: Derrick Rose or Michael Beasley and Russell Westbrook
2007: Greg Oden or Kevin Durant and Mike Conley
2006: Andrea Bargnani or LaMarcus Aldridge and Tyrus Thomas
2005: Andrew Bogut or Marvin Williams and Chris Paul
2004: Dwight Howard or Emeka Okafor and Shaun Livingston
2003: LeBron James or Darko Milicic and Chris Bosh
2002: Yao Ming or Jay Williams and Drew Gooden
That's a tad misleading. the players that were taken at 2 and 4 in those drafts wouldn't necessarily have been the 2 Danny would have taken. Darko being a prime example.
In those drafts, Wall, Rose, Bargnani, Bogut and Howard were not clear number 1 picks. There was definitely a debate over who to take.
I don't think it's misleading when those were the picks that were actually selected. What would be misleading is to say Danny (or any GM) would have had the foresight to pick the next 2 best players in the draft and avoid all busts (not that you're saying that).
Sure Danny probably doesn't draft Darko #2 in '03. Some believe Danny would have taken Durant over Oden in '07, and I bet he takes LaMarcus Aldridge over Bargnani in '06 too. That's the good of Danny, I'd bet he'd hit on those picks.
But he'd probably also make some bad picks. I bet he takes Marvin Williams over Bogut, Paul, or Deron in '05. He showed '06 that he'd rather have Telfair instead of Brandon Roy or Rudy Gay. If the C's were drafting high enough in '04 (say #7), he's probably passing on Deng, Iguodala, and definitely Big Al to draft Robert Swift. Rumor was if the Celtics were unable to trade their pick in '07, Danny was going to take Yi Jianlian at #5. (Really all guesses on my part, nothing much other than my own opinion to back those up).
We can't assume Danny is going to nail those picks while the GMs drafting around him whiff.
Here's the history of #1, #2, and #4, which shows how a wide variety of different GMs drafted. To me it looks like #1 beats out #2 and #4 most years.
(and yes I know Darko went 2, but in this scenario you don't mess that crap up)?
You can't just assume that, though. If there is one guy who is a clear cut number one, and after that a handful of lesser, but still exciting, prospects, history says you should DEFINITELY take the clear cut #1.
History says that the clear cut #1 player will likely be better, but history doesn't say that your team won't be better with the two slightly lesser prospects.
The James draft shows that, I think as I believe you would be better with Melo and Bosh/Wade than if you just had James. Even though James is a better individual player. Especially on a deep team filled with quality role players like the Celtics.
How many drafts are like '03 though? With 4 perennial All-Stars in the first 5 picks? It's an interesting debate for '03, but most drafts don't have have so many A+, A, A- picks right away. (Side note: even if most GMs pass at Darko in the top 4-5, are you more likely to take a gamble at him at #4 after you've taken a sure thing like Carmelo at #2? Like how we've seen similar reaches with Kedrick Brown and Fab Melo when the team was able to make a safer pick right before). Probably the next closest recent draft was '08 in terms of contributors at the top, but you still run the risk of taking Beasley or Mayo. Several mocks didn't even have Love or Westbrook going in the top 5:
http://www.nbadraft.net/mocks/2008_nba_mock_draft.html
http://sports.espn.go.com/nba/draft2008/columns/story?columnist=ford_chad&page=MockDraft-080626
http://www.nba.com/draft2008/board/mock.html
I see it as: in a few drafts you would be better with #2 and #4, but most drafts you'd be better with #1. So to me the odds favor #1, unless you think your scouting/player analysis is that good, which I don't think Danny's is (not that it's bad, it's just not the 100% accurate that people are looking for here).
But not all #1 picks are Lebron James. Let's just take the drafts in the 2000's
2000 - Martin or Swift/Fizer - Martin (though Mike Miller and Jamal Crawford were both top 8 which makes it a bit more interesting)
2001 - Brown or Chandler/Curry - easy choice to trade even without the other good players
2002 - Ming or Jay Williams/Gooden - unknown since Williams was in the terrible accident and never played after his rookie year (A'Mare, Nene, and Caron Butler all top 10)
2003 - James or Darko/Bosh - obviously that is easily James, but less so with Melo and Bosh/Wade
2004 - Howard or Okafor/Livingston - again easy choice with Dwight, though Iggy and Deng also top 10
2005 - Bogut or Williams/Paul - Easy choice to make trade here even if you don't take other better players (Ainge wanted to trade Pierce to get the third pick for Paul, I think he might have taken him #1 actually)
2006 - Bargnani or Aldridge/Thomas - again easy choice to trade
2007 - Oden or Durant/Conley - again easy choice to trade and I think that is the case even if Oden lived up to the potential since him and KD would have been close
2008 - Rose or Beasley/Westbrook - injuries make this an easy trade, but even if you presumed Rose was healthy Westbrook still might be better (Love and Brook also in top 10)
2009 - Griffin or Thabeet/Evans - easy choice to keep Blake, but you make the trade if Harden and Curry are your selections (they went 3rd and 7th that year)
2010 - Wall or Turner/Johnson - again easy choice to keep wall, again not so easy if you make better selections at 2 and 4 and take DMC/Favor/Monroe/George who were all top 10, even guys like Hayward are quality players
2011 - Irving or Derrick Williams/Thompson - again easy choice to keep Kyrie and again not as easy if you swap out Williams for Jonas who went 5th or Klay Thompson who went 11th
2012 - Davis or MKG/Waiters - again easy to keep, unless you take Lillard and Drummond
2013 - Bennett or Oladipo/C.Zeller - make the trade every time - now if Noel hadn't been hurt he probably goes 1 and that makes it a lot more difficult
2014 - Wiggins or Parker/Gordon - Wiggins looks like a star and Jabari is injury prone, but this one is pretty early and you still have Exum, Smart, and Randle not to mention Embiid lingering
2015 - Towns or Russell/Porzingis - Towns looks like a monster and Russell hasn't looked good, but Kristaps has also looked pretty good - Okafor and Mudiay have also looked pretty good - this one could be interesting down the line
So I have 10 to 6 keep vs. trade of actual players drafted. If you do a better job of drafting though trade wins out.