So to contextualize 2010 Joe Flacco:
10th in comp %, 10th in TD passes, 9th in YPA, 14th in YPC, 7th in passer rating, 12th in QBR.
So basically he was a fringe top 10-12 QB that season.
Would point out that a) that was easily his best season at that point in his career, and 2010 was probably like his 2nd or 3rd best overall season as a Pro in his career. It was at least on par with 2012 and I think only 2014 was objectively better.
The "knock" at this time was the same as Lamar's... playoff success.
The Ravens were 3-2 with him as a QB, but he was overall pretty bad in '08-'09 in the playoffs. Pretty much your textbook game manager.
Zero 200 yard passing games, only one game where he had a comp % over 50%, and he had 1 TD and 6 picks in 5 games.
The first playoff game of the 2010 season against KC was the first time he looked "great" in a postseason game. He also then fell flat on his face against PIT the next week, but 2010 was sort of the start of the 3-5 year "coming out party".