He actually has
Receptions 210
Yards 2,675
Yards/Catch 34.7
TD: 9
1st Downs: 33
As for the drops...he doesn't make the list of worst offenders...
http://sports.iwon.com/nfl/stats/lea...esdropped.html
As a 3rd option in the AZ offense that isn't bad. I haven't watched as many games as you, being that I'm usually trying to find a place to watch my 49ers, but few teams have a slot receiver like Welker who is the 2nd option. Comparing him to one of the elite slot receivers who is a 3rd option would be more fair. Let's look at Chris Henry (2006)
Henry also is a 3rd receiver behind two studs (Housh & 85) and is also known as primarily a deep threat. Henry has more TDs and yardage, but fewer receptions. Henry averages around 30-35 receptions per year while Johnson gets around 40-45.