I don't recall Mulan being set up in an arranged marriage in the original movie, so I'm guessing this is talking about the second one.
Mulan wasn't technically "arranged" to marry the guy. One of the king's daughters were. In fact, Mulan was completely against arranged marriages the whole time, which is WHY she nearly married the loser prince. She sacrificed herself so that the daughters didn't have to go through that pain. That isn't spineless at all. Mulan wasn't upset with the arranged marriage itself, she was upset with arranged marriages in GENERAL.

I'm confident that is not the case with Aurora. She was set up in an arranged marriage the whole time, and she didn't exactly do anything. (Now, I have not watched Sleeping Beauty in a VEEERRRRYYYYY long time, so I hugely apologize if I'm wrong about Aurora!)

@Sapling132639
Mulan was visiting the matchmaker at the beginning of the first movie, who was supposed to find a good husband for her. That's still an arranged marriage.

I think neither were spineless, but Mulan was more clueless or lost than selfless.

@Luna Ah, true. But she never was set up for a marriage, due to failing the test thing.

^but she was prepared to do it is my point. Aurora gets a lot of flack for this but Mulan never does.

It especially annoys me because people hate Ariel for leaving her kingdom for a man but hate Aurora for leaving her man for a kingdom. Damned if they do and damned if they don't. I guess the moral with Disney fans is don't be interested in men period.

:)

Aurora didn't really do much throughout her film, so it's not like we got to see much decision-making or anything from her. That said, I think "spineless" is a bit harsh. At the same time, I wouldn't say that either of them were doing the right thing either, if by that you mean going along with something that was going to make them miserable for the rest of their lives. I just think that both characters felt like it was out of their control; it just wasn't what was done in those days and they thought they were doomed to being told how to live. So yeah, not necessarily the best decision they could've made, but I think they made it simply because they didn't know how to oppose it. They weren't spineless, they were just unhappy with the tradition.