I'm with Lyn on this one. I believe the Tribes are fairly generalized, and while some have proven more capable than others in some respects, the differences probably arise more from societal pressures. As long as you are supporting your family, supporting your Tribe, I think you will be viewed in a marginally positive light. While a simple farmer may impact far fewer Matari than a warp-drive engineer, their function and contribution are recognized. However, this is not so much addressing political accomplishments.
Regarding the state of the Republic; given the situation the Matari faced in the wake of the Great Rebellion, reliance upon the Gallente in the formation of institutions that could answer the rapid expansion doesn't seem unreasonable. The friction that a lot of players see between the Tribal traditionalists and Republic loyalists seems to be a misattribution to me: many on the former side view the Republic as a foreign imposition, while some on the latter feel that the Tribals are defeatist or, in the worst case, 'race traitors'. My personal feeling is that the Republic was largely necessary to the survival of the Matari as a single body after the rebellion, but that it is a transitional form of governance which recent events indicate is on the wane. Some research into the recovery of failed states here on Earth supports the idea that, among the many factors contributing to rapid and successful recovery, were leaders who embody ethnic representation and identity as well as display traditionalism and rationality. In the Republic, they have re-institutionalized the title of Sanmatar, reconstituted the Parliament along Tribal lines, and elevated the Tribal Council above it in all non-trivial matters. The Tribal chiefs, along with Shakor, seem to be exemplifying the qualities cited, and one might look at statistics like the precipitous drop in crime as indicative of strengthening statehood.
This does not address the cultural cooling off that inspires many ethnic Minmatar to remain in the Federation, but I don't think those Matari are making a political choice.