This is a follow-up to whose lives matter? as I thought a few links that I included in reply to a comment would be helpful in a post as well. (Note: I rambled on too long, so those links will be included in part B.)
But first I want to say a few things. I've been vegan for a long time now (twelve years), and I'm sure I'm not the vegan I was when I first started this journey, just as I'm no longer exactly the same person in general. And while I believe my core values haven't changed, I wouldn't be surprised that if I looked at my posts beginning from 2008, I could find a few things that would make me cringe today. And that's because nothing is static. You change as you grow, and your viewpoints and philosophies refine themselves as you incorporate new information. That's a good thing, both personally and for whatever cause grabs your heartstrings the most.
So I would say the biggest change is likely the realization that the problem which requires veganism as a fix isn't simple, therefore the solutions won't be either. Platitudes, easy sound bites, and single-pronged solutions aren't the answer; otherwise the world would have become vegan a long time ago already. I'm more comfortable now with realizing that the solutions by necessity will be multi-pronged, have a variety of elements that some would describe as welfarist/new welfarist, abolitionist, intersectional, etc.
It could also be that change will come about quicker because of market forces, consumer innovations, environmental or economic necessity, and I'm okay with that. If more animals end up staying alive because of something like cultured lab-meat, for example, than a massive change in people's moral perspective, well, I'm okay with that too.
Another thing I've come to realize more fully is that vegans, because they're human, are complicated. Being vegan doesn't automatically make you a better or nicer or more compassionate person. There are likely as many assholes among vegans as there are in the general population, but that shouldn't surprise anyone. Infighting shouldn't come as a huge shock either. No matter how noble a social justice movement may be, it's still comprised of imperfect humans with internalized prejudices.
Most vegans are driven by a sense of compassion, sure (well, one would hope), but that doesn't mean that racism, sexism, ableism, classism, homophobia, transphobia, and on and on and on, hasn't affected the movement. Just as the world grappled at large with the notion that rampant abuse of power leading to sexual harassment and assault is more of a norm than an exception, stories of sexism within the animal rights movement were front and centre at the same time.
Right now the world is also more fully waking up to the reality that racism plays a role in every institution and layer of society (systemic racism), and while some vegans may continue to not want to deal with that, may continue to insist that our movement should only focus on nonhumans, a veganism without intersectionality at its core is like a feminism that doesn't want to include all women in its fight for equality.
And that realization (the importance of intersectionality) has probably been the biggest shift in my own approach to veganism over the years. Because at heart, the ending of oppression is what veganism is all about. Which is why as vegans, we have to fight for the most marginalized of ALL groups, including both animals and humans. Fighting against speciesism is important, but without paying attention to other interlinked forms of oppression, veganism misses the mark.
As I said, I've said too much, snort, so will continue this discussion and links in part B.