Apart from the fact you have to stand on the skid to operate the winch because of the skids, the 145 is fine for winching and the standard seat fit folds up to give plenty of room in the cabin.
Our CP flew and assessed the 5 blade 145 recently and was very impressed with it - the Leonardo TP couldn't understand how the RAF/Ascent had made such a mess of implementing it.
If it is a performance issue then it is no better or worse than the 412 which was used successfully for years.