There's a lot of question-marks on defence:
Rielly, McCabe -- known quantities.
Tanev -- very hopeful, but question-marks remain due to age, injuries, and change of teams.
Liljegren -- known, but suspect. Will he ever be a reliable defenceman?
OEL and Hakanpaa -- question-marks over health and performance.
Benoit -- question-mark over small sample size. Is his breakout year repeatable? Is there room under the cap and on the roster with the additions of older, veteran defencemen Tanev, OEL, and Hakanpaa?
Timmins -- will he be demoted, traded, or lost on waivers? Does he have any value at all to the Leafs, anyway?
All other prospects and players under contract -- Niemela, Webber, Rifai, Kokkonen etc. -- none of them are very young, and will any of them get a serious look-see on an NHL roster here or elsewhere? Are they all a dead loss at the NHL level? Is there a viable path for development for any of them?
Another acquisition -- where does the cap room and roster space come from? Significant player moves would be needed -- how and where?