I really don't think there's a reason to compare the two, and I would never lessen Dillon's impact on that team. However, you're talking about a receiver setting an NFL record, turning a good offense into one of the most prolific attacks in history, turning an already great quarterback into a statistically dominant passer. Dillon was ground and pound, he was absolutely a joy to watch but there was never a sense of "Oh my god...I've never seen something like that before". And that's where there's no comparison: some of Moss' TD catches were highlight reel, best-of-all-time receptions. Even some of his regular receptions...remember the across the middle, one-handed, how-the-hell-did-he-do-that against the Colts?
I will say this: Dillon absolutely carried the team in the 2nd half of some of those games...he was a one-man wrecking crew who kept opposing offensives off the field and bled the game clock. But Moss did what no one else could: he dominated the scoreboard...instead of having to bleed the clock, he simply caught touchdowns, basically saying "you ain't gonna outscore us".