My opinion on the sets isn't changing too much, though hearing some negative things about the QUALITY of the Imperial set has sort of put a sour taste in my mouth.

The Imperial set had the most appeal to me as an army builder, since the AT-ST (Imperial Army Regular) driver is sorely in need of a better sculpt, and that sorta fit the bill. The R4 astromech is always welcome, and of course stormtroopers can never be turned away. The Vader's sort of dejecting though, and just like the upcoming Saga Snowtrooper... WHY THE CANNON!? I have umpteen of those things already, I'm all repeating blastered out here.
The BH set has the least appeal to me, as has been pointed out by a few others... The swoop bike is a nice improvement over the SOTE swoop, but it's tough to justify buying 4 figures I already have for the bike... Like others have said though, if the deco on each figure is greatly improved I could maybe see it, but I'm just not so sure on that... I mean, nobody in the set can even ride the swoop, can they?
The Hoth set's title is a tad misleading... When I hear "Battle of Hoth", I don't expect what's given in the package. While the Taun Taun w/Guts is a nice addition for sure, the Hoth Luke, Lame Hoth Leia and astromech make it tough to stomach...
Now, had they made a "Major Derlin" variation out of a Luke figure (w/new head), and replaced Leia with a semi retooled Hoth footsoldier (Change the legs somehow and give use the upper body of the Deluxe soldier with Saga Han's arms) then I maybe would've been excited over this set. The astromech's not bad (But why not use R3-T7's body since it's better?) and the Taun Taun is ok, so I'll likely be more excited about this one than the BH set...
No matter what though, this 4-pack idea... Just like the Cantina Sets and accessory sets... isn't being given the best treatment, and Hasbro could've done better with the execution of these.
As always, Hasbro has nice ideas that they bungle in one way or another... From the army-building 4-packs in white boxes to these. There's always some lil screw-up that makes them not as cool as they COULD have been.
Too bad...