These comments betray a lack of understanding regarding how sophisticated the "5 civilized tribes" comprising the bulk of Sequoyah were. Their goal was not to create an "an Indian homeland" for tribes from other parts of the nation, but mainly to preserve some of their own cultural independence within the framework of statehood. It would not have become a reservation, nor would it "fail" as a state, any more than Arkansas or Louisiana can be called failures. Culturally, Sequoyah would have been an extension of Arkansas, southern in outlook, but with a large number (perhaps not even a majority) of its citizens being of Cherokee, Creek, Choctaw, Chickasaw, or Seminole extraction. Resident whites and acculturated mixed bloods would have been dominant from the get-go. Like the rest of the south (which the five nations largely allied with during the American civil war), it would be very resistant to granting civil rights to its black residents who may have been excluded from citizenship in Sequoyah. Oklahoma Territory would have become a state at roughly the same time. Without its eastern half, Oklahoma would be much more like Kansas, west Texas, and even Colorado. Less southern, more midwestern or southwestern. There is no reason to believe that Oklahoma territory, which was formed separately out of the western 1/2 of Indian Territory and never had political control over what would have become Sequoyah, would have resented the parallel existence of Sequoyah. Same for Texas and Arkansas.
The main reason TR vetoed the Sequoyah statehood bill was because he suspected it would be a staunchly democratic southern state, while a larger state combining Oklahoma Territory and Indian Territory might be less likely to fall reliably into the democratic camp (he was wrong, though). From the beginning, the southern attitudes of the more populous eastern half of the state dominated,