The courier would outsmart the dova any day of the week,a courier with 1 intelligence seems smarter than any dova i created,and if all else fails he could just speech check 100 him and send dova walking.
Gotta admit Dovahkiin does seem like a blithering idiot. The Nordic culture in Skyrim screams ignorance, and I think I read up somewhere that the Nords once had a god of knowledge, but he died or something, thus....well thus their lack of reverence for knowledge.
They seem to act more on their emotions.
But nah, I think the ultimate issue is just that the Courier has range and also moves faster than him, thus, the Dragonborn has practically no hope of ever catching him, being shot at the whole while. Other issues include things like the Ranger Takedown (even if you catch him, you're gonna get knocked on your ass ASAP), with perks like Paralyzing Palm or And Stay Back! only making things even more grim.