Torres had already declined and his sharpness had gone.
Torres at his best, wasn't so much a player with out and out pace that was good at running behind defences (like a young Michael Owen, Craig Bellamy), the key thing was his speed off the mark and his acceleration, his positioning was good but he was able to steal a yard on defenders from different positions and nip in with the killer strike.
Once the explosive acceleration was gone he was a much more limited threat and he wasn't ever really able to remodel himself as a player.
However you have to say that for all the "lets all laugh at Torres" stuff, he was the biggest winner from that transfer. He had already gone in to irreversible decline but he landed himself both an enormous contract and also ended up a Champions League winner, which he wouldn't have got with Liverpool.
For Liverpool, to move Torres on when they did and bring in Suarez when they did was a masterstroke. They had managed to get top value from a once great player that Chelsea hadn't realised was going in to decline, but they also managed to pick up a player in Suarez that people knew was good, but hadn't realised was potentially the best striker in the world. I would have said Suarez' reputation at the point he signed for Liverpool was similar to Sanchez when he signed for Arsenal this summer.