Cannot agree that Lucas is a better player than Gerrard was at this point in his development.
Last night, Lucas stood out for two reasons to me. The first, which was apparent to me throughout the game, was that he offered very little in an attacking or a defensive sense. Going forward, as other have pointed out, it seemed that he was afraid to try anything for fear of messing up. No doubt his 'stats' for the game would show a near perfect pass completion rate but this is a prime example of how stats can lie. In all honesty, he offered very little.
To be honest, I'm not sure where his best position is. At Gremio, I understand he played a slightly more advanced role and scored a few as a result. I haven't seen enough craft or guile to suggest that he could play this role for Liverpool as his creativity isn't evident when he is playing easy five yard passes all the time.
Defensively, I feel he's too slight to cope. Diarra, a good player, whisked passed him many a time last night and Diop simply knocked him off the ball. I wouldn't feel confident with him in the side when we come up against someone with truly world-class central-midfielders.
The second thing that stood out last night was when we were under the kosh in the last fifteen minutes, he kept giving the ball away either by hoofing it or mis-placing passes in our defensive third of the pitch. I'm sure composure will come with experience though.
As other posters have pointed out, he needs to start stamping his authority on games and not simply being a passenger. Hopefully this will come with time and experience but I'm not sure if this will be the case with Lucas and if he doesn't start performing a bit more, he could be on his way. At the end of the day, Rafa has sold players for a lot less.