None of the Table Service locations within the Magic Kingdom has very good views of the fireworks. You can see
some of the fireworks from within CRT, but it's something I recommend for guests that are looking for an alternative view (i.e., they've already seen the show and want something different). They do dim the lights and pipe in the music and some of the fireworks are visible through the stained glass windows. You won't be able to see any of the effects on the castle or Tinkerbell. Also, not all tables have a good view of the fireworks.
I think the two best options for seeing the fireworks from a restuarnt are from California Grill (Contemporary) and Narcoossee's (Grand Floridian). The California Grill has an observation deck where you can watch Wishes if you don't get a table with a view. They pipe in the music. A few tables have a view of Wishes, but those are pretty hard to come by. You can ask for a window table, but they do not promise to have one available before fireworks. If you want to eat here, I would aim for an ADR about 2 to 2.5 hours before Wishes. Personally, I like the observation deck because you don't have to deal with reflections in the glass.
Narcoossee's is my favorite restaurant in WDW. Most window tables have a view of Wishes, but the view is often blocked by folks standing out on the veranda. You'll probably have to go outside to watch as well. They do restrict the veranda to guests dining at Narcoossee's, so it's not that crowded. They dim the lights and pipe in the music (inside the restaurant and outside on the veranda). You can request a window table. I would aim for an ADR about 90 minutes before Wishes.
A few tables at 'Ohana have a view, but most do not. I would not go with the plan to see fireworks from your table. There are some reports indicating that folks do get up and move around to see the fireworks. This would be the approximate view (you can see the castle to the left of the main wall support).
In terms of IllumiNations, Rose & Crown is the only place with a dedicated viewing area for guests that are seated at a table without a view. They do not usually accept requests for tables, so if you do go, I would plan on viewing IllumiNations from the viewing area or dining early enough that you finish in time to find a spot around World Showcase to view the show. Other places that get mentioned are La Hacienda (if they are accepting table requests, make sure to request one with a view of IllumiNations; not all window tables have a view) and Spice Road Table. None of the resorts table service locations have much (if any) of a view of IllumiNations.