The best Civilization V mods
R.E.D. started back with Civ IV, and stands for Regiment and Ethnic Diversity. It adds visual variation to the units and adjusts their proportions so that tanks are no longer accosted by giant infantrymen and aircraft carriers aren't eclipsed by Renaissance Era ships. R.E.D. also changes up the formations so the units look less like they were copied and pasted into their tiles.
Get it on Steam Workshop.
Install the original R.E.D. Modpack first, then R.E.D. Xtreme to shrink and multiply your units' individual actors even more. People smaller than hills? What crazy ideas will the modding community come up with next? Civs which don't all issue identical uniforms?
With some reference help from the R.E.D. Modpack, Ethnic Units also diversifies the look of each civ's infantry and vehicles with reskins. It may not be wholly complete (I'm afraid I haven't spawned one of every available unit from every civ for scrutiny), but it makes an easily identifiable difference and is being updated continuously—as of this article's posting, the last change was made yesterday.