I've got him & like him, he's my one cranky in one of my towns.
Good house (sleek I think, maybe a bit of modern) - mainly black anyway. No surprises but he's OK to good.
I've got worse.
I think he's alright when it comes to design. He lives in my ACCF town and he's not too bad but he's not one of my favourites, he's one of those villagers who I wouldn't mind living in my town but if they offered to move away I don't think i'd hesitate. I agree with you on horses needing more attention since some of them have solid designs and the horse villager Papi is one of my favourite villagers.
Roscoe's my favorite villager of all time he's such a sweetheart and I'm kinda sad I had to let him move out due to my town theme and whatever but I love him so much and I hope to have him when Animal Crossing comes to the Switch. I also named my first horse Roscoe in BOTW and it's amazing.
Hey, Roscoe's pretty good, actually! If you want Roscoe in your town then I would recommend you get him. Another recommendation of mine is not to get two or more cranky villagers, they can get annoying! If you want Roscoe as your only cranky villager then go ahead, do it! His monochrome-styled house would be a great touch to your town.
I like some other horses more than Roscoe, but I think he's okay. Winnie lives in my town and Rudy lived once in my town and I think they two are just so adorable. That red eyes are kinda creepy and I don't think that it really fits in his design, some other colour would be better, but okay.