If you keep up with the lore and quests from zones they feature prominently in, you'd find that these themes are actually quite prevalent. This expansion simply isn't tailored to be a platform for them, semi-exclusively, as was the case during TBC.
A very interesting man named Alexander Graham Bell once said, “When one door closes, another opens; but we often look so long and so regretfully upon the closed door that we do not see the one which has opened for us.” It's true that with the re-empowerment of the Sunwell the BE's had no real need to siphon energy from anything and therefore lost a little bit of their tendency to act with the ends justifying any means required. However, it opened up a whole new can of worms for lore to tackle: what about the people who actually prefer the new methods?
This creates story among the Blood Elves, between the Blood Elves and the High Elves, between the Blood Elves and the Horde as well, even, between the Blood Elves and the Alliance by way of Dalaran. I'd say it's far more interesting that simply, "everyone hates Blood Elves".
If I had my way:
1. Kael'Thas would still be the blood elf racial leader. His 360 turn from wanting to find salvation for his people to betraying all of creation was very strange. He could have been handled better.
It's not all that strange. It's quite common for mages, especially arrogant ones, to believe themselves above corruption and/or reproach. Archimonde. Kil'jaeden. Ner'zhul. Illidan. Medivh. Azshara. Arthas (stretching).
Maybe, but you're forgetting that much of the lore that has happened since wouldn't make sense if Blood Elves had remained as they were prior to the restoration. It's likely that the rest of the Horde would view them as only slightly less chaotic than the Forsaken, meaning all these sidestories with BE/Tauren or BE/Troll relations wouldn't exist or, at the very least, they'd be strained similarly to the Garrosh/Sylvanas dialogue.
It's still there -- and in fact, most of those who actually use magic (mages, warlocks, etc.) still utilize the questionable practices of siphoning magic from lesser beings. If you take a quick glance at the Reliquary page it's pretty much outright stated that this is a major point of contention among the people. It's also likely that this is partly why Lor'themar was concerned that many Blood Elves would consider re-joining an Alliance-affiliated organization if given the chance.
It might've worked, but it would've been the stretch of all stretches -- the number of people who actually siphoned energy from demonic sources was likely an extreme minority. The reason BE's have green eyes isn't because they used demon magic, it is because they were in proximity to others who did.
I wouldn't disagree to this, I wanted to get tattoo's like that (not on my face, mind you) for years after TBC came out.