The combat controls are not for realism but for making complex moves.
What complex moves? It has four different moves, four, all of which are simple directional attacks.
In Warband beta, which I took part in, some more subtle mechanics were added to make combat more complex. That's what he meant I guess.
1) Chamberblocking: With executing the mirror attack at the right moment after the opponents does a certain attack, one is able to counter his attack. For example a left-to-right swing can be countered with a well-timed right-to-left swing that way.
2) Weapon sweetspots: Weapon attacks do reduced damage if they connect at the very beginning/end of the animation or if they hit at a bad range.
3) Stun: Heavy weapons can stun people defending with lighter ones, taking away their opportunity of attacking back and allowing a follow-up attack. This is especially true if the initial attack was charged up or had a good (movement) speed bonus.
4) Feinting: Probably started out as a bug in the original M&B, but became the foundation of dueling in Warband. Attacks can be canceled in the beginning of their animation or ready position, allowing to execute a different attack instead. Can be chained, but feint spam usually leads to axe into face for oneself against an avid oponent. There are 2 different kind of feints, early(silent, basicly just changing the ready position) and late(loud feints, shortly after the canceled attack is released). In that context the "unbalanced" tag for some weapons was introduced, that hinders their feint/attack canceling ability.
5) Crush through: Very few weapons, like hammers have the ability to partly crush through a block with a strong attack. This makes fighting with or against them unique.
6) Charged up or chambered attacks: Holding an attack for a short amount of time increases its power (damage or stun if blocked). However the maximum is set about 1 second or so. Holding for longer decreases the power again.
And probably more stuff I forgot. It is by far the most complex fighting system in an FPS-like game that I know of.