Look at it this way. The Unsullied are trained to follow the symbol of their master. Which is a more potent symbol: the whip, or the dragons of the queen who just incinerated the head slave master and burned and sacked Astapor? Dany doesn't need a dorky freakin' whip to show she's their master now.
There were men left behind at Castle Black, as well as men at Eastwatch-by-the-Sea and the other one I don't know the name of. But this is a heavy blow for the Night's Watch. Who knows how many of these men who remain loyal will even make it back alive, and Castle Black is the great Night's Watch stronghold. Also the big problem, as you state, is that it used to be a great honor to join the Night's Watch, and now the only people who do it voluntarily are those who are lied into believing it was some grand defense of the kingdom like Jon. The rest are the worst dregs of society, hardly worthy of forming the "shield to guard the realms of men".And it's impressive how the Night's Watch lasted as much as they did, you starve and insult a bunch of thieves and murderers and expect them to follow through with the ideals of an organization they were forced into in the first place? I wonder what Jon Snow will do now, is there even a Night's Watch anymore?
Sansa is pretty much a window into parts of the world in King's Landing. She is definitely one of the most uninteresting characters, either in the book or the show. Catelyn is another Stark who pretty much makes the same kind of super depressing speech every time we see her but otherwise contributes little.What's the point of Sansa anymore? Or better yet, what was her point in the first place? Every time they change the setting to her i find myself thinking it would be time better spent elsewhere. She's the most uninteresting Stark in the show and it's not like her Status Quo has changed much ever since the start of season 2.