Kings fan here, very unhappy with this trade.
Vilardi started his career at center but had a very difficult time with the demands of the position thru the neutral zone. He doesn't have speed over distance, but from the dots in he has very quick, sudden movement to gain separation. That was the biggest change to his game that allowed him to break out last year - he found out how to get the timing right to get his shot away.
Prior to that he played more of a perimeter Getzlaf like style. It was the change to wing that allowed him to have a much bigger influence on the teams offense. I don't think an 80 point aeason next year is out of the question. He loves to score and his hands in tight are spectacular. Ironically his game on the wing is very similar to Corey Perry, minus the shenanigans.
Losing Iafallo is a huge bummer. He can play from first to third LW, with good hands. He is a terrific forechecker - the best board play and penalty killing winger on the team. Scored clutch goals. Not fast, not slow, but excellent at stripping pucks and takes great angles in the neutral zone. Shocked we moved him. Newer or less involved fans don't appreciate players like him. We will miss him dearly.
Kupari has great tools, blazing speed, good hands, the occasional willingness to throw a big hit, but has been a victim of the Kings piss poor developmental team that is trying to force talented young players into roles they are not suited for just to get them in the lineup. His best use would be as a 3rd line winger, but McLellan kept forcing him into the 4c with less talented players so nearly every thing he does is of a one on one nature, lots of wide drives before cutting to the net without looking for other options. He may need some deconditioning time before you really see what he can and cannot do - it had been made very clear to him that if he wanted to be a part of the Kings that he would need to curb his offensive instincts and take a more defensive approach, and thats just not his game.