The point is, there is pretty much no rational measure which has Welker's last five years among the best in history. It is only by looking for endpoints which fit your conclusion that anything at all appears.
I'm not sure where you're getting anything about "average number of TDs a season"; Rice had 197 in 21 years, 9.4/year. Plus 10 rushing TDs. In 1986-87 (2 years) Rice had 37 receiving TDs; Welker has scored 32 in his 8-year career.
The stats I keep referencing are for SINGLE seasons, Welker has averaged 6 TDs a season for the last 5 years (nothing impressive by itself), im saying that in the history of the NFL, 5 people have had two seasons (in their careers) with 110 Receptions, 1150 Receiving Yards and 6 TDs, the ones I listed.
Welker is 62nd on the list of people who've had at least 1150 yards and 6 TDs in a season. Welker's done it twice, the same as Eric Moulds, Steve Watson, and David Boston. Except the other guys had more TDs. And the people who are really good in this stat are Jerry Rice (12), Randy Moss (8), Torry Holt (7), and a bunch of other WRs who are recognized as all-time greats, unlike Welker.
And again since I have to keep reiterating it because people keep quoting me and then putting words in my mouth, I never said anywhere that this was a better measure of a wide receiver or said that it was even a defining measure of a wide receiver, im inferring that Wes Welker is one of if not the best slot receiver in the history of the NFL. Consistency is the truest measure of talent and even though I admit a large portion of his success is the system he plays in, his numbers wouldnt be as impressive as they've been over such a large period if he wasnt that good.
His numbers aren't very impressive. He gets a large number of short receptions on a huge number of targets, and turns them into a mediocre amount of yardage and not many TDs.