Four teams come to mind right away that are worse at #2 then Thrash (or ARE): Philly, Vikes, Fins, Jags. Add San Fran, Bears, and Chawks. I'm sure there are a few more.
In the last 4 season Thrash has had 9, 12, 14, and 17 receptions and a whopping 3 td's. He is 32 years old, has declining numbers, and isn't very effective. He is a great guy to have on the team, does an excellent job on special teams, and imho should be our punt returner over ARE. But he isn't a #2 receiver anymore. He used to be a solid receiver but at this point is basically a #5 guy that plays in emergency situations.
The Eagles have Reggie Brown as their #2. Last season he had 61 catches, 780 yards, and 4 td's. As many td's in one season as Thrash has had in his past 5 seasons combined. I would gladly take Brown over Thrash.
Now that the Jaguars have Jerry Porter, Reggie Williams (10 td's last season) becomes the #2. You would take Thrash over a guy that scores more td's by himself than all of our receivers last season?
The 49ers signed Bryant Johnson this offseason. He isn't All Pro, but he is certainly a very solid receiver. The last time that Thrash put up comparable numbers to his was 5 seasons ago in 2003.
The Vikings added Bernard Berrian in the offseason so their receivers will be better this season. Last year Bobby Wade had 54 catches, 647 yards, and 3 td's for them. They also had a rookie do well for them last season (Sidney Rice, 4 tds). I would take either over Thrash at this point.
I'm assuming that by "Chawks", you mean the Seahawks. They had 3 receivers all go for more than 600 yards last season and at least 4 td's. We didn't have a single receiver with 4. They might not have an individual stud such as a TO or a Chad Johnson, but Burleson, Engram, and Branche are all very solid NFL receivers and much more effective than James Thrash.
The Dolphins (not sure why we want to compare our wr situation to the worst team in the NFL) can also probably do better than Thrash as a #2. They signed Ernest Wilford this offseason and his numbers last season were 45 catches, 518 yards, and 3 td's. Not the best numbers, but once again I'll just point out that Thrash hasn't posted those types of numbers since 2003.
Of the teams that you mentioned, the only one that I think has a #2 receiver worse than Thrash is the Bears. They lost Muhammed and Berrian and gained Booker and Lloyd. So you're basically looking at Lloyd vs. Thrash.
If we lose Randy Thomas w/o adding another OG of his level it won't matter who we have playing WR - and the opposite is definitely not true of Moss. Moss would be a huge loss but not as much as RT. Recent Skins history proves that.
Nobody is saying that we don't need oline depth. Of course we do. But we don't need to spend a first round pick on an offensive lineman, let alone a guard. Good guards can be had in the middle rounds of a draft.
The Vikings proved if you have a really good OL and RB you can be competitive w/o a QB, WRs, or a D.
The Vikings didn't even make the playoffs. They also had a guy named Adrian Peterson that dominated the entire league.
NE won four SB w/o WRs and lost one with the best group of WRs in the NFL
New England won 3 Super Bowls, not 4. They also have a guy named Tom Brady as their quarterback. Perhaps you've heard of him?
Cleveland got better this year mostly because of all the additions they have made to their OL.
They also finally got solid quarterback play and got monster seasons from Braylon Edwards and Winslow.
The Cards have one of the best group of WRs in the NFL - lots of good it did them.
The Cardinals stink because of their defense, which gave up 330 yards and 25 points a game last season. Their offense and their receivers are what kept them in games last season.