Hello, Why are the horses smaller than they should be in Bannerlord? Horses are as big as donkeys.
When will the authorities fix this problem?
It kills our enjoyment of the game.
That depends on the breed of horse.
Mongol horses are around 12-13 hands to the withers (approx. 1.2m to the shoulder - a 'hand' is roughly 4 inches = 10 cm - the withers are the height a rider sits from the ground, although a tall saddle may add a few extra cm). They are the same size as a Shetland pony (to which they're related).
Many Anatolian horses were a similar size as late as the Ottoman Empire. Europeans used to laugh about the 'tiny horses' ridden by the Ottoman horsemen, but those small Anatolian horses were strong, agile, and swift, with a steady 'pacing' gait - perfect for a horse archer, and would keep on running, long after the fat, European horses were 'blown'.
Turkmene horses (probably the tallest historical breed) could be up to around 16 hands (approx. 1.6m to the shoulder), the same size as a modern thoroughbred (which are largely descended from them), but they are skinny, with long legs and necks. They are probably descended from the Ancient 'horned' horses of the Medes and the Persians, the bones of which indicate they were a similar sort of size and build.
Roman cavalry horses were somewhere in the middle at around 14 hands, but much thicker set, with a barrel chest and strong legs, most European medieval warhorses were descended from those, and modern draught horses, but they only got bigger slowly, by selective breeding, and there was nothing like modern draught horses until the modern era. The myth of the massive 'Medieval warhorse' is just that, a myth, European warhorses were solid (to carry a heavily armoured man), but not tall.
Most modern breeds are taller than their historical equivalents, thanks to selective breeding over the centuries, and have been 'improved' by crossing them with Arabs (not tall, at around 13-14 hands, but otherwise generally superior), and other 'desirable' breeds, so have little in common with their ancestors even a couple of centuries ago.
Donkeys (asses) vary in size according to breed too, as do mules, some are as little as 9-10 hands, but average is around 11, so a similar size to a small Mongol horse.
Mongol horses (and Shetland ponies) are strong, and can carry a tall (6 foot), full grown man in armour, Shetland ponies were ridden by vikings (who then dismounted to fight).
To go back to the OP's point, I'm not 100% sure, but I think he might be right and the horses in Bannerlord might be a little on the small side overall, but if they were too big that would look far more ridiculous, and besides, they're enough of an obstacle to movement as it is.