If things like Jungle Canteen's grilled steak, fried chicken, savory noodles, and baked fish are too wild for your teens (keeping in mind that when you strip away the flamboyant descriptions of each dish, there are several that are quite traditional), I'm not really sure what to suggest. I think the best best is probably Liberty Tree Tavern, where they can get simple meats, mac and cheese, and green beans, etc.... plus, it's all-you-care-to-enjoy, so if somebody only likes a couple of the meal's components, they can make a meal of just those. It's one of my childrens' reliable favorites.
If you think they'd like a character meal and don't mind a lengthy time investment (our dinner here took almost 3 hours, thanks to a 30+-minute wait to be seated, sluggish character rotation and 2 kids who really wanted to meet all the characters), there's Crystal Palace (buffet with Pooh characters). We found the food to be excellent (a step above typical buffet fare in terms of freshness and flavor), with lots of variety to please everyone.
I wouldn't waste dining plan credits on any of the other TS options in the MK -- Tony's and the Plaza are a la carte, with fairly pedestrian food; they're great if you want value paying out of pocket, but on the DDP you're trading good money for an unremarkable sandwich or some just-thawed chicken parm; and Cinderella's Royal Table will cost you 2 credits for a
very limited prix fixe menu (no less exotic than Jungle Canteen's) with a fuzzy view of the MK and a few more squealing little girls than is really necessary in any situation.