But from looks and stats alone, the only thing the Redguards show have over the Nords is skill and discpline, they should lose in strength, hardiness, and raw power.
"There is no question that Redguards, while currently lacking the cohesiveness as a society to form effective armies, are excellent warriors and unmatched at guerrilla warfare."
Skyrim used to be the dominant human nation, but clan wars back in the First Era tore it apart and surrendered primacy in terms of military might to Cyrod (that no Nordic "king" has ever held full control over Skyrim since the days of the Ysgramor clan also speaks to the inherent divisive nature of the Nords). Then later on in the First Era, the Yokudans arrived and slaughtered everybody in their way (claiming Hammerfell in the process), wrecking the Bretons and Orcs who held the region at the same time and cutting into territory that is claimed to have been owned by Skyrim.
During the War of Bend'r-Mahk, Skyrim was able to reclaim some of that lost territory thanks to the Redguards not being a cohesive force (the two large groups wouldn't work together), but Tamriel is rightly scared ****less of what happens when the Redguards are actually operating as a united force. When they are, they've never been beaten (and when they're doing so it occasionally results in a HoonDing - last time that happened, Hjalti's most powerful dragon follower was slain by Cyrus and the Empire forced into a treaty with Hammerfell before they were allowed to take it on as a province).
Essentially, the Redguards are usually scattered and divided into tribes. When they come together as one people, united, then be afraid. Be very, very afraid. In that sense they are much like the Argonians when the Hist are in a command-control position. That doesn't even get into the Ansei (if any still live), which is part of the skill and discipline you noted.
"We get serious about fictional girl underpants, and kid around when it comes to topics like world hunger." ~Teepo on CAGN