I think that for it to be sound strategy for GOP legislatures and governors to switch to a ME/NE system there must be enough states doing the same thing so as to make it unlikely that the move would bite the GOP in the behind. I count 6 states where the GOP controlled both houses and the governorship both prior to November and currently and which recently have voted Democrat in presidential elections: FL, PA, OH, MI, VA and WI. Had all 6 switched to the ME/NE EV allocation method prior to November, and had the vote been exactly the same as it was in November (a HUGE “if,” since obviously the Obama campaign would have targeted marginal CDs in, say, PA, instead of just making sure to get out the vote in Philly), then Romney would have picked up 16 EVs in FL, 13 in PA, 12 in OH, 9 in MI, 7 in VA (it should have been 8, but Rigell’s VA-01 gave Obama a 50-49 victory) and 5 in WI, which would have given Romney 268 electoral votes, one short of throwing the election to the House (and two short of a majority). And had Romney been able to carry one of those states, he would have reached 270 EVs (since the statewide winner gets 2 bonus EVs under the ME/NE system), so we wouldn't have the anomaly of having the switch cost the Republican the election.
Of course, Romney was very fortunate to carry all those marginal CDs in FL, PA, OH, VA and MI, and had Obama done a smidgen better in the suburbs he would have flipped a handful of EVs, but had that been the case Romney would have had no chance with a winner-takes-all system either.
So I think that the GOP legislatures in FL, PA, OH, MI, VA and WI should consider switching to the ME/NE system, but only if all of them are willing to do it. It wouldn't guarantee a GOP victory in 2016, but it certainly would make it an easier road to 270.
Bush was elected President twice without a single EV from Pennsyvania (although admittedly by the skin of his teeth in 2000)
I think a more likely problem is that if GOP legislatures in swing states dropped the "winner take all" system because they never win statewide in Presidential elections, Dem controlled legislatures would neutralize the effect by doing likewise.
The good news is my first glance at the map shows there's not many areas where they could do so in order to erase new electoral votes the GOP would get out of FL/PA/OH/MI/VA/WI. The Dems could probably pick up quite a few electoral votes out of right-of-center moderate southern states if they switched to the Maine/Nebraska system, but those states are currently controlled by GOP legislatures so they'd stick with winner-take-all. The Dems would have the most to gain from changing Texas, at least on paper, since they virtually zero chance of carrying it statewide in a presidential election right now, but due to sheer population and congressional districts they could gain quite a few EVs by allocating them based Congressional district winner. There are large swaths of Dem-controlled areas in Texas, like the panhandle by the Gulf of Mexico and most of the major cities. However, the state legislature would never play ball and switch from winner take all. Arizona, same problem for the Dems on a smaller scale. The only state where they could use the legislature to change the system and might benefit is West Virginia, but it only has five electoral votes so at most they'd gain 1 or 2 EVs by that method.