Hernanes is the type of player that is currently too good to play for Liverpool. He also plays for a team that is better than Liverpool.
If Liverpool wants to grow, they have to play young players that are the stars of tommorow.
The older players they have to buy are Mikel Arteta-type players. Players that are very good, but never became stars because in their country there are better players for the same position (Arsenal IMO did really well buying the likes of Cazorla and Arteta). IMO Liverpool should take a closer look to Newcastle, they really did fantastic transfers the last two years.
I know Newcastle is below Liverpool in the EPL, but that is just bad luck with important players who are out (a litle bit like Bolton, a team that normally would never go down, also a team that had a very good manager in Coyle).
The other more experienced players that Liverpool can buy, tare Sneijder types: older players who've seen it all and just want to earn lots of money.