The AI definitely does things to target the player, and did so in Warband and original M&B as well. For example, there's always one enemy NPC on the battlefield who is actively targeting the player in every battle, and if killed, another takes over the task. I've seen the last enemy archer or skirmisher surrounded by enemies in melee, but STILL trying to shoot the player who is nowhere near him. It's not that every enemy NPC is actively targeting the player, but it's become painfully obvious in each game that ONE will do so. When the enemy is down to the last one or two men, and they're far across the map from you with your other soldiers chasing them, it's annoying to hear arrows or javelins landing nearby, because YOU are still the primary target. In original M&B, line of sight didn't matter, they'd target you even on the other side of a hill (it's frustrating to be hit by thrown weapons or arrows without ever even seeing the enemy), but that mostly ended with Warband (they could still fire through tree foliage that blocks line of sight, but not through the trunks or over hills).
I've also seen the AI go WAY out of its way to raid the player's village first, even though it's on the opposite side of the faction's area from the enemy, with them passing by several other villages to reach it. As pointed out, they'll also send an army to retake a player's castle that's far better defended than other NPC-owned castles that are actually closer to the enemy territory, at least one of which was taken from that faction earlier. Again, I suspect that the game always pits one enemy against the player, who will go out of his way to raid or siege the player's personal property. It does tend to get annoying when you've destroyed a lord's army for the fifth time, but he keeps coming back and doing it again because you're his assigned target. Turn away for a moment, and he's back again for the 6th time, sieging your castle or raiding your village.