That's a good question @Andrew.What would you define as your ideal audience?
For me, my ideal audience would be those who enjoy videogames not only as entertainment, but art as well. Some of my videos for videogames such as We Happy Few and Darkwood, from time to time, I comment on the art-style, aesthetics, game design, concept, story, characters, etc. of the videogame I'm playing. Sometimes, what I say eventually becomes like an in-game review of the game in-play, and that's added alongside the gameplay without deciding to have it in my video beforehand. Doing this allows my gameplay commentary and gameplay itself to feel more natural and not forced so as to desperately attract a larger audience.
I try to cater to people who don't have anything to do and want to watch someone play videogames and enjoy them as "entertainment objects," but sometimes, I feel that I need to tackle a more entertaining-aspect because if I put myself in the shoes of my audience, I would wonder how I would feel if I watched others play videogames. Using what I learned from doing that, I could better understand how I make my gameplay videos, focusing on how long they should be, what would the audience prefer seeing should I compare one clip to another, and what games have not been showcased on YouTube yet, and take that as an opportunity to expand my audience among those who look for videogames to play, but can't find any, or don't know where to start.
When it comes to catering towards an audience, it's definitely important to first decide what you want your audience to be, because once you attract that audience, they will likely remain your only audience for the entirety of your YouTube career. After long hours and painful days of work making videos, once you attain an audience, the next thing to focus on is loyalty, and that comes from defining who you are as a public figure among those whom you've intrigued, and from there, you have to decide the next step.
It's your YouTube channel; you make the choices.