Hmm, interesting.
This is a complicated issue because only one person kicked her out House, but I don't Dawn was wrong.
First of all, i'll discuss the potentials.
They had every right to question Buffy's decision.
Most of these girls were mid-teens and had already seen Buffy's decision making lead to death. Thats not an issue, they were scared. I know that every single person in the world would(or at the very least should) question leaders that place them in that situation without knowing why.
Faith had come, and ok she was a convicted killer, BUT she was proof that Buffy was not the ONLY Slayer. If a Slayer was to lead the group, then its quite right that the potentials question if the right one is leading.
Xander, Willow, Giles and Anya, there is the issue.
They know exactly what Buffy has done for the last 7 years. They have fought side by side at times and saved by her more often then I care to remember. Sometimes her plans have been reckless BUT she always comes through. They let their fears add doubt to their own thoughts. Thats my biggest issue, they forgot who they were talking about and at one point even validated the 'Faith as leader' stint which is doubly wrong because they know her too.
Its not a matter of Faith being good now, its a matter of Faith showing she still isn't strong enough to lead an army.
Dawn, however, I believe did the right thing.
BUFFY
I can't watch you just throw away everything that"” (looks at Xander and at Dawn, who's not meeting her glance; Buffy holds her head up high) I know I'm right about this. I just need a little"” I can't stay here and watch her lead you into some disaster.
DAWN
(stands, walks up to Buffy, softly) Then you can't stay here. Buffy, I love you, but you were right. We have to be together on this. You can't be a part of it. (Buffy blinks her eyes in disbelief) So I need you to leave. I'm sorry, but this is my house, too.
Thats the part where Dawn says Buffy has to leave.
She isn't telling her she should leave because she agrees with what the potentials and the Scoobs are saying, she is agreeing with Buffy. Buffy knows that if they are to succeed then they need to work together and she also knows she can't watch them if she isn't part of it(and Buffy really couldn't be second to Faith) so Dawn does the thing she has to do. She tells her that she needs her to leave the house.
No, in my opinion in this entire scene Dawn is the ONLY one who does the right thing for the right reasons.