Thanks for the reply. I'll push back on each of these, though:
Bernie is having a hard time rallying Democrats, which doesn't bode well for his ability to organize and campaign in the general.
That depends on what type of 'rallying,' and of whom exactly. Clinton has an overwhelming amount of support from the Democratic establishment, who have certainly rallied behind her. But as I've seen it, that's about it. Sanders, conversely, has a lot more enthusiasm behind him from those outside that group (as well as some who are inside it). His campaign has been more of a 'grassroots' effort, which while not as well oiled a machine as Clinton's, is not woefully disorganized. If he were to become the nominee, I imagine people would fall behind him much as the GOP has behind Trump.
Bernie has qualities that poll very poorly with the general populace (Socialist, Atheist, etc)
This is a fair point, but in spite of this, he still has a considerably higher favorability rating than Clinton or Trump. Moreover, I would wager that the vast majority of people grossed out by socialism and atheism will be voting Republican regardless. Feel free to disagree.
General Election polls this early out aren't usually indicative of the final outcome. If they were, the fact that Bernie is only +10 points over Hillary, despite the fact that's she's embroiled in a scandal, as well as the fact that he hasn't been the target of any negative attacks from the Republicans, would be extremely alarming.
Yes, as I noted, I'm aware that polls this far out are very noisy, and Clinton is weathering yet another scandal in a laundry list of them. What concerns me, however, is that this email situation is probably only going to get worse. But it points to a bigger issue. Many of Trump's supporters are backing him in virtue of the fact that he isn't one of the 'political elite' (I think this is pretty naive, but that's what many think nonetheless). They see politicians as corrupt and self-interested, and Trump is running on the promise of giving that system the finger. Hillary embodies precisely the sort of corruption and self-interest that he's (ostensibly) railing against. My fear is that Hillary is the best possible opponent the Trump campaign could have hoped for. On the other hand, what could he throw at Bernie that he wouldn't wear proudly? "Socialist!" Yep. "Atheist!" Sure. And he can't really play the "establishment!" card there. My point is that I don't see where Trump could possibly make Sanders lose any ground.
I'm not saying you're wrong...just saying that there are some serious counterpoints to consider.