Business class, to me, is all about the seat. There aren’t many airlines where the food and wine are remarkable, though better business class offerings will be fairly good. Mostly you want personal space to work effectively and to sleep so that you wind up at your destination reasonably rested rather than beaten up.
The best business class experiences make the overall journey seamless, from checkin and security to a lounge to wait for your flight to priority immigration on the other end and even an arrivals lounge for a shower when you land (so you can go straight away to meetings, and because your hotel room may not yet be available with early morning arrivals).