The idea of negative reputation is certainly not intended to be a barrier to any earnest attempt to participate, even if that attempt is to propose an idea that's very likely to be unpopular. I wouldn't call it an oversight either, because we're aware of the problems users encounter when learning how to navigate meta.
I'd venture to say it's not wholly "rep" that causes trepidation, seeing something you put some time into writing up and explaining get decorated with dozens of down-votes is far from encouraging, and it happens frequently enough that people take on a pretty reasonable fear of it happening to them. So, the problem isn't really exclusive to just MSE, it's just exacerbated here because loss-aversion instincts have more to cling to.
However, we really need folks that come here to talk about changes they'd like to see to have some kind of stake to hold; we'd like people to at least give what we've got a shot before pitching in to help reinvent it all.
At the same time, however, we need to be receptive to talking about barriers to participation on meta for folks that have used our system and have things to talk about. If the way things work here is keeping people that actually use our sites from talking about how they could be better, that's a problem. And, if you ever have a problem where the canonical solution is get a thicker skin, well, then you have two problems.
We're looking at making some changes to how meta behaves based on tags that people apply, and helping people better select which main tag (e.g. discussion, support, bug, feature request) to use. People get frustrated with people asking the same basic support questions over and over again, and that manifests in voting pile-ons. So one idea is just making much easier for people mark support questions as duplicates and more aggressively culling any that don't get upvotes. If we do that, maybe we wouldn't need down votes on support questions.
Bugs don't need upvotes, they need "I can reproduce this" buttons, and they need to tie into our back-end bug tracker (currently Azure). It's really hard to differentiate upvotes between "this was entertaining" and "this is happening to me too", or down-votes from "this wasn't written well or is a dup" from "can't reproduce". That makes bugs difficult to triage.
We (employees) need to be able to blog on meta without actually asking a question, but we need to build a more blog-ish archetype for that.
So I'd say it's more a work in progress that should have had a higher priority for a while now, but one that we haven't forgotten about. The per-site metas on 95% of our sites function just fine and people indicate that they feel good about low barriers to participate on them. The problem is here with the 'Senate' of meta sites (MSE) and similarly high-traffic parts where attempting to build consensus can feel like a pile-on.
We also need polls implemented much more deliberately.
I'm going to be proposing some ideas for some experiments in 2019 after our product teams settle in a bit more (we've got like 6 more hires to make at the time of this writing). We're not going to do anything drastic like overhaul everything in the middle of the night, but we do need to have conversations about what's not working with each area that meta tries to serve, and address that area by area.