I think the bashing was due to the fact that all he did last year was be a Kick Returner, which in today's NFL, usually means you have a player who is receiving touchbacks.
That's not Roberts' fault, it's just how the game is now.
Also, as a Wide Receiver, Roberts is clearly a back-up player.
What has surprised fans this year, myself included, is that Roberts has shown how good he is as a Punt Returner. I do not recall one game from last season where he returned one punt.
That has been a big positive for Roberts. It makes me wonder why he wasn't pulling double duty as a returner last season.