In response to your poll...the bigger need is play making PG since we have players that need a PG to be effective, especially Amare.
However I believe we addressed both those issues with Kidd and Camby respectively.
To the topic...Kidd is right that Lin would always play in one high paced gear. Lin would sometimes just crash into people and I always knew he would get hurt or be too tired. I admire Lin's hustle and his desire to win but you have to play smart and sometimes he would just run out of gas because of how he played the game.
Kidd sounds already like a good mentor and was a high tempto PG like Lin is. But Kidd learned to play good in the half court and was effective on the championship Mavericks team.
Kidd can teach Lin how to find players in certain spots. When to attack the rim, etc.