Yes, it did. But it's good because they only did 25 eps, as opposed to, say, making a WTF ep 26 which tried to squeeze a million of bullshit answers into twenty minutes of running time, destroying the whole story in the meantime and contradicting pretty much everything you might have understood up to that point, as well as doing stupid things like killing off Dio for example. I'm really glad they didn't do that.
Last Exile could have been a really memorable anime if the plot and main characters were more solid, 'cause I loved the setting and fictional technology.
The whole story just felt like a vaguely motivated train of barely connected events.
Assuming, hypothetically, that they made ep 26 such as I described above, it'd indeed have made the story *much* worse and destroy any sense of connectivity. But in its absence, the plot isn't particularly bad, and in a way, the unresolved story ending at ep 25 is perhaps better off this way, leaving some things for the viewer to answer.