It's also probable too that after the plague of undeath, it makes the value of land that wasn't as great now much higher since what was already good land has been despoiled. Makes Alterac's position much higher especially if it's used properly wouldn't you think?
It's unclear to what extend the Scourging of Lordaeron was also scourging other places. It hit Lordaeron mainly because that was the strongest kingdom, then they got Archimonde in who destroyed dalaran, and then it seems that the majority of the force travelled to Kalimdor to take on the Nelves. However, we know that Gilneas was incidentally attacked, and we know that places like Southshore or Arathi weren't really affected. Same for Kul Tiras. As such, it may be that Alterac, with teh exception of Arthas attacking the Blackrock, wasn't particularly affected, and therefore there's no blight to clear up etc.
to be discarded as filthy Orcs
horde has worked with black dragons
Sure that's a concern, and looking at Neferian does clearly demonstrate that he thinks of the Dark Horde as tools, but I would note as well that externally, it appears that the Blacks have been reliable and useful allies for at least 15 years. They were one of the first factions to ally with the Orcs, and continue to support them in various ways.
Why nobody remarked on the small fact that one of the Fellowship that faced the Four Horsemen... suddenly mUTatEd into a DRAGON? There should have been an interrogation as to "why have you hidden your nature so?" followed by the decision of "you, working with us? Thanks but no, thanks"
2 - we did have a talk with him and the only person who isn't allied to us 100% (cause vrak is our blood brother, sesk is our teacher/bodyguard, slivanas doesn't care, Kaldrin himself is the dragon) sally was permantly made mute but conserding she was knocked out right after she might not remember and Grok response was after talking to him
The only people who'd mention it would be Castillian and Whitemane. While Whitemane was indeed injured, she can probably still write, and in general I don't think either of them would have a great deal of remarks to make on the matter. Castillian is a Legion agent, and thinks you are too, which means he's fine with just letting you handle it until he can report back to Varimathras (who presumably is over in Desolace with the Forsaken now). And Whitemane, given she knows you can use the Light, is also ok with it because you're in close conference with high level paladins. She therefore trusts you to deal with it. However, to specifically address this, yes let us imagine that Grok mentioned at some point that he would manage it, and that the others are indeed fine with it.
3. as far as I can tell ofc the black dragons are focusing more on the southern part of the eastern kingdoms and see alterac as a way to gain legitimacy (neferan has the dark horde, onyixia has stormwind and both are near the portal to where deathwing is)
I won't specifically remark on this as I don't tend to go into what others are thinkign because yknow its agency quest and that means uncertainty too, but yes that's certaintly something they might be doing. Don't put all your eggs in one basket etc.