On current form he's probably the best there is at the moment in world football, so he would be a massive loss to any side that he played in. We rely on him way to much to score and create goals, and this is a massive problem in games where teams put 10 men behind the ball, because a lot of the times Gerrard is the only who can do something special to open a team up, especially when Torres was injured.
As for where we would finish without him, well id say we would still finish fourth but we would be miles of the top of the league. The reason i think we still qualify for the champions league is that we still have some high quality players like Alonso, Mascherano, Rieira, Torres a good defence and a great coach in Rafa who can get results from mediocre players (why he buys mediocre players is another subject), so were very difficlut to beat, so i dont think we would lose many, but we struggle to score goals without Gerrard. I thinks its vital that next season we bring in some offensive quality, to share the burden with Gerrard and Torres and finally make this team look complete after 5 years of trying. We can start buy getting rid of dead wood like Kuyt and Lucas etc and bring in a quality striker, an attacking midfieder a right sided midfield player and a right back, all which we desperately need. Whether we have the money or not is another problem.
Lets just pray that Gerrard is fit and healthy ASAP, other wise were in big trouble with some vital games coming up.