Two ways you can look at this really.
1 - That he isn't good enough for Liverpool at the moment. Barely featured under 3 Liverpool managers (Rafa, Hodgson, and Dalglish). Had a relatively successful loan spell at Norwich, but that was only 3 starts. And towards the key end to the season, he lost his place in the side. Then, the infamous Inception Loan within a Loan. Neither club fancied him, and he only made 1 start for Rayo in the whole season. And that was in the cup.
2 - That he hasn't been given a chance. Etc etc.
We all got excited by him in the youth teams, the reserves, and at youth international level. But he has never really progressed and kicked on (for whatever reason).
I, like most in here I am sure, would welcome him moving on, and getting some game time. If that means he needs to drop a division, or go to a less glamorous club, then so be it. He needs games to prove his ability.
A player like Leto, until his injury earlier this year, is forging himself a decent career in Greece. Paletta went back to his homeland for a few seasons, but is now in Serie A with Parma. San Jose went back on loan to Bilbao, and earned himself a permanent move there after good season. Barragan left to join Deportivo, and is now at Valencia (via Valladoid). I am sure there is more.
If he is good enough, he needs to prove us that we were wrong to let him go. I hope he does (and we have some sort of buy back of course), because he has a lot of talent. But that talent, for whatever reason, hasn't manifested itself in to a top quality player. Maybe it will, maybe it won't, but he needs games.