I would agree on most of these, but would have to strongly disagree on a few of these.
Nofoaluma - As bad as he has been recently, he had 5-6 very solid years where he improved each year and was a highly regarded winger. He has just aged poorly due to his own attitude and personality. His downfall is on him and him only imo.
Liddle - Is a solid first grader and was among the dragons best this year. He showed promise here too, but he couldn't string enough games together without getting injured. Have to give him a pass given his horrible run of injuries.
Sironen - Was never good... In fact you talk to people who played in around the juniors with him, he wasn't even a top 10 junior in his own age group. The only reason he ever touched first grade was because of his last name and his size. Rugby League nepotism personified. So i agree that he was a disappointment, but he should never have been there in the first place to even be a disappointment.
Garner - Nothing was ever expected of him. He was a Manly junior who didnt make it there, went to the Roosters lower grade and didn't make it there either. He was never touted as a young talent or ever expected to be a first grader. In fact, the Tigers were the club that developed him from a non-first graded into a first grader. His performances were just as good from his first game with is to his last. He should be regarded as a development W not a disappointment.
Tuilagi - Similar to Garner, was never thought of as a first grader even at the Storm, a club renowed for making first graders out of fringe players. Tuilagi has played for the Storm, Tigers and Manly and played his best football for the Tigers out of those clubs. That says it all really. Most fans were disappointed when they heard he was leaving. Bet none are disappointed now.