No one is perfect, and no one is a perfect spouse! We all have flaws. It is not good to idealize someone too much before marriage, because, after marriage, we discover they are only human beings, and it can open the door to disappointment.
However, there is no harm in considering your spouse perfect *after* you are married. It might avoid many arguments. :)
There are many factors that go into a happy and lasting marriage - for instance, physical attraction, personal compatibility, commitment, treating someone nicely, and the willingness to compromise. None of these relate specifically to hijab.
It is recommended to marry someone of faith who is conscious of Allah. If hijab reflects a person's faith, that is a good sign. However, hijab is not a guarantee of a happy marriage or even of shared views about Islam. So it is safer not to stereotype and to look at the individual instead.
However, it is good if there is agreement about the matter of hijab. That is, if a young man is looking to marry a girl who wears hijab, and the girl wears hijab, then this is a source of agreement and one less possible source of conflict.