I think it's perfectly valid to evaluate the draft on the day after. And again 3 years down the road.
We do this with trades all the time. My apologies for mixing sports metaphors, but the Iglesias for Peavy trade made perfect sense at the time it was made. The team took a spare part and turned him into a #4 starter at a time when the outlook for Buchholz was anything but certain. It also worked out reasonably well, despite Peavy's struggles in 2 playoff games.
Where reasonable people can disagree is whether it was worth addressing the QB position with a 2nd round pick this season, versus addressing the team's other needs. I personally am torn on the matter, so I'm going to punt and see how it works out 3 years from now.
But I don't agree that the Patriots decision was the outcome of a broken or flawed process. Sometimes a good process is going to produce decisions that seem questionable or flat out do not work. The draft is not an exact science, and I doubt any team blindly uses computer projections to pick the player they need to draft. Deciding that age 37 is the time to start finding a future starting QB does not seem outrageous to me, nor does using a valuable draft pick to do so.
As to the value of a 2nd round pick, something I saw mentioned upthread, I took a quick and unscientific look at the 2009 and 2010 drafts. These are players that by now should be in the prime of their NFL careers barring major injury. Of the 64 players drafted in the 2nd round in those 2 drafts (which included Patrick Chung, the immortal Ron Brace, Darius Butler, Sebastian Vollmer, Rob Gronkowski, Jermaine Cunningham, and Brandon Spikes):
21 players have been noted by pro-football-reference.com as the primary starter for the majority of their years (at least 3 seasons for 2010 picks, and 4 seasons for 2009 picks). This category includes Spikes and Gronk, but not Vollmer due to his injury history. There is some arbitrariness to my process, but I'm just looking at overall trends, so there will be some obvious errors at the individual level; hopefully these errors even out.
20 have appeared in fewer than 65% of the teams games in that span in any fashion (special teams, sub, starter). Since I consider 65 to be a minimum passing grade, I label these as busts. This includes Brace, Cunningham (no argument there).
9 have had at least one Pro Bowl selections, and 4 have had multiple, including Gronk.
So, roughly one third bust out, one third become depth/ST guys (including Chung and Butler), and one-third become solid starters. There's also about a 5-10% chance of hitting a Pro Bowl caliber player. Most would argue that 2nd round picks are indeed valuable given those numbers.