There are other things that Enterprise "got right" but two things that stand out for me are the uniforms and the introduction of the MACOs.

*The uniforms: * They are practical, they make sense and they totally seem plausible. They even have pockets which also makes sense. As for as I know, the uniforms from TOS, TNG, DS9 and Voyager didn't even have pockets. The Enterprise uniforms had patches which clearly identified what ship you served on. Make sense, right? The uniforms from TNG, DS9 and Voyager appeared to be interchangeable with anyone serving on any ship or outpost on Starfleet.

The uniforms from Enterprise also appear made from a more durable material. Remember how Kirk's tunic always seemed to getting ripped every few episodes? Even Picard had the same problem from time to time.

*The MACOs: * Considering the many times the Federation got into conflicts with different alien species its astounding that we never really saw any specialized fighting force until Enterprise. Remember that episode in TNG when Picard, Crusher and Work went to that Cardassian planet to find evidence of a biogenic weapon? Wouldn't it have made more sense to send a MACO team? The Federation certainly could have used them when fighting the Borg, the Dominion or pretty much anyone else the Federation got into trouble with.