It's an odd comments because there has been a number of quality converts who have had great success. Failures seem to be the minority, not the majority.
The Reds had Sailor who showed his quality at times despite struggling to adjust to the nuances. They also recently have had Chambers, McLinden and Shicofske who were all very good players for us. Had they stuck around longer in Chambers case or some across earlier in the latter cases they could have all potentially been Wallabies.
The Tahs had Rogers, Tuqiri and Izzy who have all been highly successful, whilst Blacklock and Tahu were failures. Tahu would be the only one to be considered a massive flop simply due to the fanfare and cost associated with him.
Saffy at the Rebels really wasn't much chop, primarily due to injuries limiting his performances, yet as a former Aus Schoolboy, he's hardly a convert anyway.
Tomane has been great at the Brumbies and Peter Ryan was great in their early years.
Brad Thorn did the hard yards early and has arguably been a greater success in rugby than he ever was in league.
People don't deathride the player's success. It's just when they come across on a big pay day with large fanfare there is scepticism about how quickly they will hit the ground running and therefore if they are worth the money. If a guy's on a 3 year deal and he's performing well below that for the first year that's a big percentage of the contract duration.