Benitez was building towards the future, Houllier just couldn't be arsed evidently (OK I'm being harsh).
A 22 year old Warnock, wasn't given a single game by Houllier. NOT ONE!
Three years after Houllier left, Rafa had pretty much got rid of everyone of his players.
Only Finnan, Hyypiä, Riise, Kewell, Gerrard and Carra survived.
Technically neither Gerrard nor Carra were "his" players.
So let's look at the present day squad. Three years have gone since Rafa left and who do we have left?
Reina, Agger, Skrtel, Johnson, Lucas.
Then add, Shelvey, Suso, Sterling, Kelly, Robinson and Wisdom to that.
There's probably more but my point is, Rafa left a legacy, which is still alive.
Now I don't know what legacy Houllier left but whatever it was, Rafa quickly killed it .
How many games did Rafa give Warnock and how much of a success has he been since? He's at a mid table Championshp side now.
Anyway, Houlliers didn't like Warnock or vice versa because Warnock left Villa not long after Houlliers arrived.