Balance ... hmmm being able to reverse the state of prone by a minor action instead of a move...?
A low-Heroic-level magic item lets you do that.
It's one of those weird little blindspots that has nettled at WotC era D&D going on 20 years now. Little things that are almost mundane, but the system makes impossible, pointless, or possible only with magic. Rolling quickly to your feat, impossible without Acrobat Boots. It's something a kid who's taken a few Aikido classes can do. Other games have 'instant stand' - not D&D (though PF, maybe?)
Using a spear for its reach advantage, and a shield - the basis of the phalanx, and a mainstay of military doctrine for thousands of years - strangely impossible. But, a kusari-gama or whip with a shield for a reach advantage, or a magical animated shield & two-handed spear, or even just get up on a horse, and it's no problem. Alexander the Great would not have been amused.
Fencing with a rapier, side-on stance, and the other hand used only for balance. Or any style using a one-handed weapon, alone. Very effective IRL, the former, at least in the realm of fencing & dueling, strictly inferior to pointless in D&D.
Shields: +1 or 2 AC, vs up to +8 for armor, yet re-enactors find that most attacks are stopped by the shield.
Parrying/Defense: Skilled opponents are harder to touche in fencing, or hit in medieval re-enactment, yet proficiency plays no part in AC. It's all abstracted into hp. (to be fair, 4e did scale defense with level, and 3e had Combat Expertise, so that's more a 5e blindspot).
...and, I could go on, but let's close with INT, to bring it back on topic: In RuneQuest, for instance, high INT added to your attack & defense %, as did several other stats, even the supernatural/spiritual POW. D&D goes all-in, one stat for attack, usually either STR or DEX. (Again, 4e's an outlier.)