I think of the latter
I don't believe most Oromos today are just assimilated people and not much mixing with the original Gallas happen. Most Oromos weather they were assimilated Somalis, many Ethio-semitic speakers, or others, they tend to have higher level of Omotic among them relative to the population they deemed closer to them. I think the Original Oromo brought more Omotic admixture.
There are still many Ethio-Semitic speakers left in Southern/Eastern Ethiopia, If Oromos were just assimilated from the former group than the difference wouldn't be striking even physically.
I don't believe most Oromos today are just assimilated people and not much mixing with the original Gallas happen. Most Oromos weather they were assimilated Somalis, many Ethio-semitic speakers, or others, they tend to have higher level of Omotic among them relative to the population they deemed closer to them. I think the Original Oromo brought more Omotic admixture.
There are still many Ethio-Semitic speakers left in Southern/Eastern Ethiopia, If Oromos were just assimilated from the former group than the difference wouldn't be striking even physically.
