Last year I took my then 14 yr old neighbor to MK for a very long day as part of a five day Orlando trip. I thought he'd think the character meals were uncool and just for little kids, but I was so wrong. He enjoyed the Pooh gang at CP, but he really loved the LTT meal. He is a huge Goofy fan, and the look on his face when Goofy came over to our table was priceless. Minnie was flirting with him and he just blushed so much. I got great pictures and we made some great memories. We're bringing his 14 yr old brother this year for five days all at WDW, and the 15 yr old has requested dinner at LTT again, even without Goofy. ( I think he wants another "date" with Minnie).
It all depends on the kid though, I don't think the younger one will get into the magic as much, but he might surprise me too.