IIRC, the MSM decided to go silent on Palin in February. I suspect they liked the results so much, they have kept to that strategy.
As for tactics, the whole field of possible GOP candidates seems to have adopted them. I think they are all afraid of announcing their candidacy for fear of becoming a target of the MSM & Left. Except Trump, that is. He relishes the fight.
That is EXACTLY what the GOP needs in a 2012 candidate, an eager willingness to take the fight to Obama & Co., using EVERY weapon in the political war chest. That is why Trump & Christie are so appealing. Both relish the fight & intend to win every battle.
All the rest are weenies! They are running PC campaigns, fearful of attacking Obama; more worried about their hair & makeup. A McCain redux. They will lose to Obama with this strategy of polite non-confrontation. Boehner/McConnell have set the tone of compromise (with the devil). The GOP field of possible candidates are following suit. Anybody who rocks the PC boat gets attacked by others on the Right, mostly elitists.
Right now, there are only 2 Pubs I can think of that could verbally DESTROY Obama in a presidential debate: Trump & Christie. I would very much like to see that, for it is well deserved.
Palin has been tearing Obama a new one everyday for the last two years. I have yet to hear Christie say one bad thing about Pres Obama.