It is easier now, but it used to be more difficult. I've diversified a lot in terms of race, sex, gender, body-type, etc., in the last couple of years, as my skill in drawing such things has grown. But that diversity is something I have always worked towards.
I rebelled early against what you call "media normal" - and by early, I mean elementary school. I've been drawing since I could hold a pen, and have been making up stories to go with my drawings all along - and ever since I first started, I've been fighting against the common ideas of what main characters should look like.
Growing up, 99% of protagonists in the stories I encountered were white, blonde and blue-eyed - and ever since I first started making up my own, my protagonists were brunette and brown-eyed. I would probably have made them people of colour as well, if I'd been aware that was a possibility - I grew up in rural Sweden, and the only person of colour I knew for the first 10 years of my life was my best friend, who was adopted from India.
I knew, even then, that there was something wrong with casting just one physical type in the heroic roles. I was a white, blonde child, but even I knew that couldn't be right. Still, it was a struggle to overcome my tendency to make characters who looked a certain way, because the stories given to me all depicted the same, non-diverse type of cast. If all media tells you this is what people are like, and you are provided with no counter-examples, it's difficult to realise they're wrong.
Of course, diversity goes beyond physical traits, and I work hard to be inclusive of all kinds of people in my various stories. Working in mostly scifi/fantasy settings means I can be a little more free in how I depict these things, but there's still an amount of research that has to be done so that I can feel comfortable including some things.
For example - one of the main characters of Grassblades, a little girl, does not speak. She has fully functioning vocal cords, and she can speak - when she chooses to do so. But she hardly ever does, because she suffers from a form of selective mutism. This means that she restricts her speech to communicating with only one other character in the comic right now - and even then, she tends to speak in monosyllables and short, 2-3 word sentences.
I did some reading on this beforehand, because I knew I wanted the character to be more or less mute, and interact vocally only with the other main character - but I needed to know if this was something that happened in real life - and if it did, I wanted to be sure I wasn't getting it wrong. When dealing with something as serious as a disability, one needs to be respectful.
I hope I've been able to pull it off.