Here's a few numbers to go with the opinions. This is from ESPN's pay area so I won't copy and paste the whole thing, just enough to show what a lousy season Samuel had.
Patriots as a team, Regular season, not including game against Miami
Depth Att Comp Yds TD INT Pen Yds/Att
Short 291 198 1745 8 2 24 6.1
Medium 94 47 871 6 1 43 9.7
Deep 83 30 1064 10 5 125 14.3
Total 468 275 3680 24 8 192 8.3
Ellis Hobbs on the Season
Depth Att Comp Yds TD INT Pen Yds/Att
Short 29 18 181 0 0 0 6.2
Medium 15 4 55 0 0 25 5.3
Deep 14 3 101 1 3 0 7.2
Total 58 25 337 1 3 25 6.2
Asante Samuel on the Season
Depth Att Comp Yds TD INT Pen Yds/Att
Short 41 21 158 3 1 6 4.0
Medium 27 13 305 2 1 -10 10.9
Deep 17 6 260 1 0 0 15.3
Total 85 40 723 6 2 -4 8.5
He acknowleges that Hobbs played against mostly the weaker part of our scheudule so he adds :
"From Weeks 13 to 16, the Pats faced three teams ranked near the bottom of the league in passing (Buffalo, New York Jets twice and Tampa Bay). In those four games, Hobbs had 22 passes thrown his way and allowed only 3.4 yards per attempt. He also intercepted three passes. Samuel allowed 5.9 yards per attempt on the 18 passes thrown at him, intercepting one pass."
I realize the arguement can be made that Samuel got the #1 WR more, although with those week 13-16 stats those teams barely have #1 WR. Anyway, those are the stats.
Edit : I bolded the "Yards per Attempt" stat as the table is formatted badly and is hard to read.