If you are looking for a nice view of the city while having lunch , then visit the WTC Tower at the Osaka’s Port area. Actually, the food is OK but the view is beautiful specially on a sunny day. I wonder if they have dinner there too.
Take the City Subway: Chuo line and get off at Cosmosquare station. From the station you can either walk or take the monorail and get off at World trade center mae station. From Cosmosquare station it is just about 5-7 minutes walk passing by the Immigration Center.
The restaurant is located at the 48th Floor of WTC tower. Lunch for 90 minutes is 1550yen including drinks and ice cream 🙂