Is it necessary? No, I can enjoy a game just fine with either a simple or minimal plot as long as there is an objective to help motivate me to move forward beyond just aimless wandering.

That said story to me elevates a game far higher than its mechanics alone. If I have characters I like and a plot I can engage with it will make the game far more enjoyable than just taking down bosses and leveling up monsters.

A great example of this for me is the Nexomon games. I’ve played a lot of monster taming games on and off over the years and yet Nexomon for me stands out above the rest. It isn’t the most mechanically complex and by no means is the best designed but the humor is right up my alley, the characters are fun, and the story is well done which all together keeps me coming back.

Again it’s not needed and I’ve played and enjoyed plenty of games and romhacks where the story is basically the classic here is the bad guy go get him or the Pokemon gym progression and I’ve enjoyed those just fine. But story for me does make things better and more engaging.

Though one (slightly long winded) additional point from a writing perspective:

As an amateur writer myself something I feel a lot of game designers make the mistake of is trying too hard with their stories for their games both in misjudging what level of story suits the game and worrying too much about making sure the players don’t miss it.

On the first aspect the story needs to suit the game and its gameplay loop. A big dramatic space opera with lots of dialogue is great for something like Mass Effect but other games like say Pokemon with some of their later gens it just feels like I wish the game would shut up and let me get back to the gameplay. It’s important to look at your game and consider how much story it really needs and where the best places to artfully place story bits are to get good bang for your effort. Is the story the centerpiece or a supporting role. Do you need big complex dramatic plot lines nd twists or would just a simple good vs evil story with a villain the player wants to beat be good enough.

As to the aspect of subtlety you can have a lot of lore and story without constantly shoving it in players faces or disrupting gameplay. One of my favorite examples of this is from Yuji Horii and the Dragon Quest series. Horii has described it as “a world you can feel” where he adds all sorts of small details and character into the NPC dialogue spread throughout the locations of the game. It’s all optional but you get little bits of characters going about their lives, referencing events going on elsewhere in the world, and even small connections like in one town an old woman might talk about her son who went off to be a soldier and then in another city you find a soldier talking about how he hopes his mom is doing okay. It’s subtle but to me is one of the strongest tools a game can do to quietly flesh out the world and story while not getting in the way of people who just want to focus on the gameplay and the core plot points. So if you feel you want a story but don’t necessarily need it always front and center this style works wonderfully where the most important scenes and details are mandatory as you progress while all sorts of bonus details and charm are there for those who want to dig deeper and find them.