The Lore surrounding Redguard's (more properly Ra Gada) is extremely interesting, you just arn't hanging around the right people. The Ra Gada brought us Memory Stone's, Left Handed Elves, the Shehai (spirit sword) and extemely unique and complex culture steeped deeply in tradition. In a word, the Ra Gada are awesome
As for Imperial's, you really don't see what lore describes the Imperials as in the games, they are lumped into one 'race' and you lack the distinctions of the diffrent cultures of Nibiean and Colovian, not to mention they completely transformed Cyrodiil from what it was origionally described as in lore. For instance, the Imperial City is supposed to be made up of several islands, and more like Venice with canol's, gandalas and entire towns built upon bridges connecting the islands and the landscape is supposed to be more jungle than forest. The Imperials themselves are varied depending on where you go, and you just don't see that sadly, so it can't be the lore.