The way I saw the match, Johnson and Enrique were the main problems, followed by Shelvey and Suarez.
Johnson (primarily, but that may be my biased eyes, touche') and Enrique committed countless 'unforced errors' that surrendered possession of the ball, killed off our patiently built-up attacking momentum and were, overall, disheartening.
Agger was picked off for the first goal (it happens to the best CBs, and it was a well-practiced set-play, sometimes they do work as planned) and simply beaten for the second. I, personally, think that Reina was partly at fault for the second but that may be too harsh.
Suarez has been out of form for a few games. He's simply that good that even when out of form he's a real threat. Vs WBA, he was simply ineffective, and he called his own number a few too many times. They say that the way to get out of a scoring/shooting slump is to keep at it. Well, unfortunately, that only works in basketball. Shots-on-goal are a precious commodity in football.
Lucas will be just fine, and he's coming along nicely. Comparing his current play to his pre-injury play, and then comparing Essien's likewise, Lucas comes out ahead. Lucas still 'looks' like the same player, just a bit slower in his reaction time. When Gerrard is on song defensively, we don't really lose much. When he's understandably tired, we do with Lucas in his current condition.
Assaidi on the left flank with Henderson in Shelvey's spot might, with hindsight have worked better for us. Still, in all candor, and given we were finally granted a soft penalty and had Gerrard taking it (which he did WELL), why we didn't go up 1-0 with about 1/8 of the game still to go is only down to Foster making a world-class save.
Carragher may have learned a lot and adjusted to BR's system, but he still does not move properly after he passes to Lucas and/or Gerrard.