Eh ... I'm going to go out on a limb and say I personally think one does have to have some level of dysphoria to be transgender just as a matter of logic alone. If I understand, an unhappiness with your assigned gender (which, again if I understand correctly could be either with your gender roll in some way, physical unhappiness, or both, is why one would want to consider going through anything related with the very long, expensive, permanent, difficult to reverse, life altering processes in the first place) is known as gender dysphoria, which is what transgender is called in the DSM now. So ... yeah, it's kinda a requirement, and I certainly think that some people have more dysphoria than others, though I don't think that this makes one more or less transgender.
I guess in my mind, one is either unhappy with their assigned gender to some degree, which makes one transgender unless it's the result of a different psychological or medical issue, or one is not, which makes one cisgender, complex transitions or not.
To not have dysphoria would mean that one is A-OK with ones assigned gender. So ... why would someone transition if they're just peachy with there gender? That implies one is cisgender, and common, and something I think that gets lost in some people's minds is that ... that really is ok!
I have a blog on tumblr and I love it. However, it's ... not always the greatest blog site as far as the community. There's a lot of people looking to find something that makes them special or looking for a reason to be angry, sometimes going to the trouble of creating reasons for both on that site, and it's almost always some 13~20 year old who just hasn't figured out themselves. Some of them most likely do need to see a therapist of some kind and maybe they are transgender maybe they aren't. Others ... they just don't seem to get that there's nothing wrong with being a heterosexual cisgender person.
* I should also mention that I don't think transition, despite how much I talked about it here because that's what I'm doing, isn't a requirement of being transgender either.
** My apologies for taking what I'm pretty sure is an unpopular view, but Hex did ask. I guess I just kinda feel that someone who considers themselves to be transgender but is happy with their assigned gender and without changing a thing may need to ask themselves some tough questions.