By contrast, Trump is a moderate masquerading as a conservative caricature.
The worst part is that it looks like you guys will be stuck with an 'establishment' president who'll simply continue the status quo of funnelling money to the rich and waging wars in 3rd world countries (Hillary).
Historically, extremists on the liberal side have focused more on policy than personality, like Sanders, Ralph Nader, Dennis Kucinich, and to a lesser extent, Jesse Jackson. These guys aren't populists. They promote the interests of folk who are below average economically and civilly, raising their prospects upward toward the mean, rather than promoting the economic or moral interests of those already in the mainstream.
IMHO, that difference is less likely to attract megalomaniacs, like Trump.
except for consistently lying...
That really depends on where you're coming from, politically. Compared to some places in the world, the most "liberal" and "socialist" Democrat (no, not Hillary) is already a right wing extremist. For starters: She's a hawk. She and her husband deliberately came in to office to push the already right-leaning Democratic party further to the right. She's for enlarging the already massive surveillance state. These are not moderate positions to a lot of people. Maybe moderate compared to Trump.
Regarding whether a moderate or an extremist is more likely to win, there's little evidence that Presidential elections get decided on political positions. Sadly, personality and style are far more significant.
Of course, my preferred choice is Bernie, but with how plainly and obviously corrupt the DNC is, I don't have a lot of hope of him getting the Dem nomination and running in the general election. Maybe things will go totally haywire and both Bernie and Trump will get pissed and run as independents after the establishment railroads them both, and then we'll have a 4-way race.
If you removed gun control views Hillary could run just fine as a Republican. She's in favor of climate change policies too, which establishment Republicans disagree with, but I don't see many average joe Republicans giving a shit about it.
You are right though, she really has no extreme stances. This is mainly due to the fact she tailors her views and policies to what's popular at the time.