No team in the conference scored bigger than the Sun Devils and Herb Sendek during the early entrant period when they found out that Jahii Carson would be returning for his redshirt sophomore year. The Sun Devils probably need to make the NCAA Tournament next season for Sendek to keep his job and Carson will be a legitimate National Player of the Year candidate next season who gives them a very good chance to do that. Many think that Carson's draft ceiling is low because of his height, so it wouldn't have been surprising at all if he left after just one season. Carson's return instantly turns the Sun Devils from a team that would have been expected to be at the bottom of the conference into one that will be expected to compete for the conference championship.
The Huskies desperately needed C.J. Wilcox to come back for his senior season, and despite a number of good reasons to head to the pro level, Wilcox decided to return to Washington for one last season. The Huskies would have been left without a single proven starter on their roster had Wilcox declared, but with Wilcox coming back, they now look like a team that can once again compete for an NCAA Tournament or NIT berth.
Dwight Powell's declaration to return for his senior season makes the Cardinal look like a serious conference championship contender in 2013-14 as they return all five starters. Powell was a borderline first round draft pick, so he easily could have declared, but will now be one of the best big men in the conference heading into next season.
It appeared that Craig Robinson and the Beavers were going to get struck by the yearly, dreaded problem of guys who shouldn't be declaring leaving early when it looked like sophomore forward Eric Moreland was going to declare. However, Moreland changed his mind and the Beavers will now have all starters returning on a team that was much better than its record would suggest. Moreland's return gives the Beavers hope for a breakout season in 2013-14.
Yes, the Bruins lost freshman sensation Shabazz Muhammad, but that was more than expected ever since he signed and all of the controversy around him during his time at UCLA might have been more trouble than it was worth. Also, it never seemed like Muhammad gelled with the team, so they might be better off without him. Their biggest score though was not having any of their other underclassmen like Kyle Anderson and Norman Powell declare, especially with the coaching change.
It would be easy to declare the Bears as losers since 2013 Pac-12 Player of the Year Allen Crabbe left early, but Crabbe's declaration was to be expected and understandable as he accomplished almost everything he realistically could in college. Also, even though he didn't produce much as a freshman, guard Tyrone Wallace could have declared due to his high ceiling and didn't.
The Trojans lost center Dewayne Dedmon a year early and even though Dedmon is an ultra-talented seven-footer and the Trojans need all of the talent they can get on the roster next year, it isn't that big of a lost due to Dedmon's recent off-the-court mistake in Spokane.
The Buffs got a boost when Spencer Dinwiddie decided to return for his junior year, but losing Andre Roberson a year early hurts. Roberson's return would have made Colorado a borderline Top 10 team going into next season, but his departure means that they will have giant holes to fill in their rebounding and defensive schemes along with scoring. The Buffs will still be very strong going into next season, but probably won't be considered a national contender.
The Wildcats weren't horribly stung by the departure of freshman big man Grant Jerrett, especially since they landed touted freshman forward Aaron Gordon, but it certainly doesn't help. Jerrett was the least-productive of the three heralded freshman big men Sean Miller brought in last year, and it is likely that Gordon was going to take a lot of his minutes, but his inside-outside game would have valuable off the bench next year and his declaration has been deemed a poor decision by pretty much everyone who follows basketball.