I guess I'll take a risk here of trigger some people ^^" But be aware that I'm just giving my opinion here, and that I don't intent to offend anyone, I just wish to find a way to come with practical definitions that are useful in day-to-day basis relationship (any kind, not only romantic/sexual). Anyway.
I think people should create new "categories" to define those things, to made things clear for other people, Even for medical and scientific reasons, but also for romantic interests and stuff. I not sure if anyone ever try to create a similar stuff (if so, I'll like to know) But, so. I understand that Gender has many layers of meaning. And because of that I think they deserve to be separated in different categories with different meanings. Like, one suggestion:
Assigned gender -> The gender you are born with (unchangeable)
Actual gender -> Your actual gender (you can change with medical processes or maybe with medicines in the future)
Fluid Gender (or maybe just gender) -> the gender you want to be recognise with, pretty much the one we use today.
Gender identity -> The gender you feel you have, in relation with your actual gender.
Edited (Change the previous "natural gender" for "assigned gender")
So me:
Assigned gender = male
Actual gender = male
Fluid gender = male
Gender identity = cisgender
A common trans woman that didn't made any change in her body
Assigned gender = male
Actual gender = male
Fluid gender = female
Gender identity = transgender
A common trans woman that made a sex change procedure
Assigned gender = male
Actual gender = female
Fluid gender = female
Gender identity = cisgender
A man that was trans and didn't made a sex change procedure
Assigned gender = male
Actual gender = male
Fluid gender = male
Gender identity = cisgender
A man that was trans and made a sex change procedure
Assigned gender = male
Actual gender = female
Fluid gender = male
Gender identity = transgender
Edit: more info to better clarify my idea:
Assigned gender => You can't choose, is the way you born
Actual gender => you can change by change your appearance, like in a medical procedure, or, in the future maybe with some medicine.
Fluid gender or just gender => The way you feel about your gender, you can change that at your will.
Gender identity => Is just a comparison between your actual gender and you fluid gender. if they are the same you are cis, and if they are different you are trans.
Anyway... Opinions? specially of trans people? Do you disagree? ^^"