Yes, Buffy was always the leader but she didn't usually tell the Scoobies "you are coming with me whether you want it or not, if you don't want to come you are not allowed to be around me anymore". They tended to help on their own volition. This is quite different from the way armies work - in an army you usually can't say "Sorry guys, I don't like this plan, see you tomorrow. If you are still alive. Have fun.". Also, a leader who says she can't trust her "troops" can't expect anything better in return.
Let's go through the events again - Buffy is dead tired but yet she decides they need to act immediately, for no particular reason other than her hunch. She decides not to wait for Spike and Andrew...I don't even know why, for all she knew they might have returned with info about Caleb's Achiles Heal and she never tired of repeating "Spike is our second strongest fighter". She calls her best friends untrustworthy. She can't spare a few minutes to stand by Xander's hospital bed. Her position as a general in the eyes of the potentials is based on her Slayer stregth, not planning abilities and now there is another Slayer around. Of course her "troops" are going to mutiny!
She didn't do just by relying on her hunches, you know. the whole premise of the show is that the Scoobies friendship and teamwork saved the day again and again. So maybe she should have recognized that her friends might have some point and are not doing that just because they can't stand her precious Spikey or have suddenly fallen in love with Faith. The plan that defeated Adam wasn't Buffy's, she overcame Angelus only through the help of Spike and following Spike's plan, she couldn't have knocked out Glory without Anya thinking of the hammer of Olaf and the sphere of Dagon, etc. So yes, she fought off everyone by relying on sometimes intuiotion but primarily on well crafted plans and help from the people (and vampires) around her. Not by coming up with some half-assed excuse of a plan and then declaring people should fall in line and no other plans are to be even discussed.
She could have kept him chained 24/7, you know. And she spent a lot of time in the school anyway. And most importantly, the safety of her frinds should be way more important than Spike's safety - even we forget friendship Willow is potentially way more powerful than Spike, so better tool for General Buffy.
Well, we at least agree that Buffy was always the leader. That's a beginning. And, no, she never had laid down any "my way or the highway" ultimatums, and she even went so far as to bail out whichever one had so stupidly jeopardized the entire war by giving in to their emotions rather than acting sensibly. Remember Giles with his flaming baseball bat in Season 2? Or Willow and her bag of knives in Season 5? Buffy
And being "dead tired" doesn't figure into the equation at all. Sure, she was tired. She was also probably sore, hungry, dirty, and she might have even had an ingrown toenail. None of those things altered the fact that they were fighting a war, the enemy was at the point of establishing a position of superiority, and action was required RIGHT THEN. Buffy said that she was willing to discuss plans, to strategize as much as time permitted, but time was of the essence, and a lot of idle conversation and bitching from the troops wasn't going to get the job done.
And Spike, precious to her or not, was undoubtedly, even with Faith there, the greatest and most experienced fighter at her disposal. He was worth the entire gaggle of Potentials combined, and you could toss in the Scoobies as well. That made having him there a risk worth taking. (Willow, by the way, was not, and never had been a greater fighter than Spike, or probably even Rona, for that matter, broken arm and all. You might have noticed that "all powerful Willow" only participated indirectly in any actual fight. She put up a barrier against the Turok Hahn, but couldn't maintain it. Granted, she activated all of the Potentials, but one single Bringer could have stopped her from doing even that much if Kennedy hadn't been there to protect her. The reason Buffy didn't take her to the vineyard in the first place was that magic is no good in a stand up fight. Before she could have gotten an enchantment halfway verbalized, Caleb would have twisted her head off)
In defeating Glory, Angelus, Adam, and even Dark Willow, Buffy most certainly did have the support and help of her friends, and that was all that she was asking in "Empty Places." If she had gotten as little support and backup fighting any one of those former Big Bads, they wouldn't have been in the position that they were in against the First Evil, because that previous Big Bad would have killed Buffy and taken over the world.
But the others "fell into line" all of those other times.