I think pool have paid too much for keane.
Depends on how he performs.
In the current market, it's a fee you would expect to pay for someone of Keane's quality and affiliation to his previous club. They didn't want to let him go so Liverpool were never going to get him at a bargain price.
People will compare his price to Fernando Torres, but to be fair, Torres didn't come from another Premier League club. Otherwise you could have added another £10m or £15m. The same will apply to David Villa when/if he moves, he'll probably move for £10m-£15m less than he would have done if he was at a Premier league club.
Keane is established and should do a very good job alongside Torres. On paper the two should hit it off very well and Keane, based on his performances for Tottenham, will be an improvement over Peter Crouch. Crouch left for £9m-£11m, only because he was in the last year of his contract.
Benitez's want for £15m would have been realised had this not been the case. Essentially he's not worth that.
The market price has moved up for everybody. It's always been ridiculous for English-based players who come from Great Britain and Ireland - especially if they've established themselves in the league and been anywhere near consistent.
Keane has about 3 or 4 years in him but if Liverpool seriously challenge for the title (it's been a long time coming) or win another European Cup and Keane plays a significant part in that, he'll have been worth it.