O'Sullivan, who returned home with the tourists over the weekend, reckons his Irish players can put their tour experiences well in the forthcoming season and beyond, making them all-round better players, despite the overall 3-0 Test result and the lack of Saturday chances for some.
"I think the (Irish) players, in particular the ones playing at this level and even the guys who haven't made the Test side, guys like Denis (Hickie) and Gordon D'Arcy, who have been unfortunate not to make the Test side, they're learning hugely and they're realising that they are able to operate at this higher level," O'Sullivan told the Press Association, before leaving New Zealand soil.
The Corkman reserved special praise for Munster lock Donncha O'Callaghan, who rose in the pecking order of the tour second rows with some doughty displays.
"Malcolm O'Kelly is another guy who I think would have had a huge impact on this tour and we'll never know now unfortunately, but now that Mal isn't here I'm glad Donncha has stepped in.
"He's gained huge respect around the squad. There are guys who wouldn't have known him because he hasn't played lock for Ireland but he's now found huge respect and deservedly so. He's made an impact everywhere really because he's everywhere on the field, he talks in the dressing room and he's very funny around the camp as well. Fellas get a kick out of him. His character's come out and that shows he's comfortable where he is and that's great."