Yorick is pretty good, I don't understand what exactly makes him bad. He's bad jungler and that's about it. To me he feels like a weird mix between Heimerdinger and a melee ad caster like nasus or garen. His ultimate can also turn the tides of a teamfight. I ulted my Irelia one time and she practically laid waste to the other team by herself with the ghoul.

But yeah don't jungle with him, I don't know what makes him bad at it but he's really bad at it. At least compared to other junglers I've used he is. Perhaps I don't know how to do it right, but it feels like he's just not a jungler. He's really easy to get creep kills with anyway and Famine gives you a decent amount of hp to stay in lane without even leveling it.

I like to start off with Doran's Blade instead of shield because Famine gives you health back so you don't need the health regen as much. The little amount of health won't make a difference in a life or death situation 9/10. You should be generally passive unless you have an advantage in lane. Doran's blade gives you two of Yorick's favorite stats, health and attack damage. It's simply the best choice in my honest opinion. Philo is good if you're having a slow non-aggressive game. Mallet is awesome on him even though it doesn't give much AD. Atma's and hexdrinker are also great items and help your defenses against certain types of damage. Wriggle's doesn't feel good on him, at the beginning of the game when it's best he's better off with other items and later on it doesn't make as much of an impact.

I ulted one of our carries last night, and she died, came back to life, and ran away ><

Yeah that happened to me before, I use it kinda like how I use Kayle's ultimate. Use it while you're fighting (instead of to save people/yourself, since it doesn't really save them) on yourself or whoever's getting focused. You generally should go for high dps allies that are within range of whatever targets you want and both the ally and the ghoul will proceed to put out insane dps, then if they die they'll still be tearing people apart. It's pretty awesome when coordinated well.