What if we end up with a shy player with limited technical ability? 
I'm afraid I'm just too old now, but thanks for the thought.

Seriously, I see no purpose in loaning Shelvey out. I can't see what he gains from it now, and only see for ourselves the loss of a midfielder with drive and forward momentum, and a willingness to bugger things up if they are not working. Given Gerrard's age and fitness, I don't think we should be letting a player with those qualities go.
I also think, if Rodgers has a system in mind, that Jonjo should be here to learn it and get used to it as quick as possible. I rate Henderson too, and think the two of them, with Lucas, could be the basis of a very sharp possessive midfield for us for some years to come. If we buy Allen, great, but I don't see what purpose it serves gaining one future talent and giving another future talent away. And Allen isn't here, Shelvey is.
Lucas, Henderson, Shelvey, and Aquilani, Mr Gerrard of course. To me that suggests ball retention, good forward movement, and a nice dash of devil-may-care. Like a very good football team's midfield ought to look like.