Why create a new identity? You may see as a necessary thing to do, but I can't see any purpose given how majority of us already have a common Somali identity, both through ethnicity and nationality. Even if we were to create a new identity, then it should not be 'compromising' on our ethnicity, but rather a new one on a national level (as much as I don't agree with).
Speaking of your given example, prior to 'Somali identity' as you call it, we already had everything we have today except the name.
We had a common language, xeer/customs, our clan based society which were quite spread out all over 'Somaliweyne' and whom we shared a common identity (patrilineally based, born into a Somali clan), despited falling under different states and jurisdictions and the list goes on.
The creation of new identities are caused by different factors and usually become widely accepted after a long period of time.
Like the Somalilander identity, if it continues they will see themselves as a seperate ethnicity in a few centuries.
I do agree with you on that the Somali one is necessary as of now, otherwise people would be lost and assimilate with other cultures which we don't.
We should strengthen our current identity till we become confident of it (most aren't now)
and nationality is important, but I believe we need to also strengthen our muslim identity in connection with the rest of the ummah.
The Muslim identity should be above all others.
In realistic terms the xeer is dying out and people are going with the federal system in Somalia as more and more people move into the cities. It will take time, maybe 50-60 more years but eventually xeer will be a thing of the past.
We should create our own new culture instead of clinging onto the past.
Somalia needs more philosophers to think deeply about these issues as well.
Anyway all these big ideas need hardworking and I'm not down to do any of that rn