Liljegren is an NHL player, so comparing them doesn't really help your argument. Also, your statements about him are pretty misleading. He's played 48 out of 51 games since joining San Jose (only Ferraro has played more), and averages the 4th most ice time. The idea that they bring offense and nothing else is wrong. And I'd rather have inconsistent offense than the consistently garbage offense, transition, and defense that we're getting out of guys like Benoit right now.
"That is why offensive defencemen have shorter leashes because if they can't provide the one thing they are supposed to be good at they'll put someone else in who can provide something else." That's illogical. A defensive defenseman is just as capable of failing to provide what they are supposed to be good at. And our current problem is that we keep throwing them out there. We're not trying someone else who can provide something else. We have options, but we didn't even bother to see what they could provide in preseason.
We had more than enough preseason games to give one of our top defensive prospects coming off a great rookie year more than 14 minutes all preseason. Niemela and Villeneuve had zero chance, but Myers, Benoit, Rifai, Timmins, Kokkonen, Mattinen, Webber, and Mermis all did? If that's true, then you just proved the bias true. What have they all shown?
Niemela has done more to deserve a shot at the Leafs than a number of those players, as well as players that were given more opportunity last year. But we're also not even talking about Niemela having a spot on the Leafs right now. We're just talking about not burying him, not holding him out of even preseason, and not tossing away a prospect that has shown decent potential.