If he can sit for a long meal, you should be ok. There's no extra entertainment though, Citricos is purely about the food and the eating experience. The atmosphere is more refined than Narcoossee's, which has a very casual feel to it. I don't find it stuffy or uncomfortable in Citricos though, they're very pleasant and welcoming.
I don't think it's 'over the top'...so the main issue is really just can the kid can handle a 2 hour meal.
FWIW, I think Citricos is MUCH better than Narcoossee's in terms of food and service.