Graphics is important, but IMO gameplay is essential, without engaging gameplay you just have a shell of a game. Galaxy's Edge is a good example of that, really good looking, although IMO not better than Brindleton Bay and Selvadorada as they fit the style of the game more, but very little gameplay and what there is doesn't carry over well to the existing games
Another example of this is FPS's of the 2000's. For 10 years they emphasised breathtaking graphics, but gameplay stagnated and atrophied. Other types of games came along and grabbed the public's attention. Shooters almost lost their crown as most popular games (if you don't include casual gaming and The Sims (which "hardcore gamers" like to pretend dont exist)). So modern shooters are now including new gameplay, as well as stunning graphics.
EDIT Also, another thing to keep in mind is how your graphics age, which is important if you want to have a long lived game. TS2 graphics seem to have aged better than TS3, and TS4's will probably age well to as generally speaking more stylised graphics tend to age better. Also, they are often cheaper to produce and easier on your graphics card.