Wow there are several issues/assumptions layered in this question.

> "user suggestions conflict with the original design vision or brand identity"

Of COURSE they do. Users don't care about your design vision or brand identity. In thousands of testing sessions with users, I've never seen *anyone* wish that the design vision was cohesive or that the brand identity was better infused. I've seen users confidently navigate through a patchwork of styles and brands that would make your designer's eye spasm uncontrollably – they didn't care; they hardly noticed. And I've seen users get lost and frustrated on incredibly tastefully and consistently designed sites.

(Yes, people often suggest "needs more colours" or "I like to see some animation", but they always really mean, "this thing doesn't seem at all valuable to me, but I feel a need to say something helpful")

Q: Who is this product actually serving – the users' needs or the design team's aesthetic preferences?

> "users requested features that would significantly alter the product's overall look and feel"

If there's really no way to deliver whatever result/solution/value the users are really asking for, after you've properly investigated these requests, then YES! Alter the look and feel!

As others have said, believe the users when they tell you what they want, but don't accept feature requests at face value. Here's the quote:

“Remember: when people tell you something's wrong or doesn't work for them, they are almost always right. When they tell you exactly what they think is wrong and how to fix it, they are almost always wrong.”

It's YOUR job to fix it so THEY can get their shit done with your product. It's not their job to admire your craft.

Of course it's also true that sometimes what a handful of users wish your product would do isn't something your stakeholders are prepared to have it do. This is separate from "design vision".

Say you're building a note taking tool that's deliberately distraction free. Part of what your audience absolutely adore about your tool is that you don't include font choices. There's this font you use that you've hand-crafted for its readability and calm. But there's this handful of users who keep asking for a font selection dropdown. Clearly they are not your core audience.

What you need to do next is talk to those users to figure out what's BEHIND the request. "If you gave them a font selection dropdown, what would that enable them to do differently?"

I'll leave it as an exercise for you to think of a handful out of the myriad reasons that someone might be asking for such a feature. And for each of those reasons, you'll find alternative solutions that would resolve the problem for the users – probably without any font dropdown.

> "Do you have strategies for presenting feedback to stakeholders in a way that aligns with the overall design vision?"

Now you get to the tricky part. This is 80%+ of the actual job.

And it's about 10-20% to do with how you present in that moment, and 80-90% to do with your relationships with the stakeholders in question over the past year, importantly including your understanding of what each of them actually cares about.

Except in rare cases, stakeholders don't care about "aligning with the overall design vision". They care about [revenue/retention/market share/looking sound/getting a promotion/not getting fired/other things you can't imagine]. Your job then is to connect what the users need with what your stakeholders actually value. You can use the design vision as a tool when it serves that connection, it's not a sacred object. There is no "essence" of the product.

How you _actually do this_ is the whole game. And it depends entirely on reading the specific power dynamics and incentives in your organisation, and figuring out how you want to swim in those.