Updated, added more counter-arguments:

I agree with most of what you're saying.

I’m very interested in the 50% curation, but I’m also concerned it’s just funneling more rewards to those who already have a lot of Steem Power.

I think this is a non-problem. All SP users would want to accumulate anyway, so why does it make a difference with a lot of SP? The rich will surely get richer regardless, if they don't waste their potential. The problem is getting voter's self-maximisation actions align with the behaviour that ought to be rewarded on the platform, which is curation / distribution / supporting curation services. The action has to be almost synonymous with SP accumulation, it's not a bad thing. I think with this, even the likes of @freedom, @haejin, @trafalgar will start to use their votes for the greater good.

Unless we adjust how curation rewards work, those with little Steem Power would earn very little rewards via curation so how will they ever get ahead, even if their content is great and begins to get voted on?

They can work for curation groups like @curie which has already established a decent workflow that adds to the platform that can be replicated. Also, with a curation economy actually going on, more valuable contributions will likely get rewarded.

Re: about flags:-
Reddit has downvotes even for the end of retaliation, by the way. It's something users will need to adapt to. It's likely a feature that adds more to the platform rather than the other way around, imo.

Part of me still thinks the problems here are psychological. If huge whales are trying to extract too much value instead of using the value they already have to protect and grow the collaborative commons we have here, then they essentially destroy their own provisions. If, instead, they thought in terms of rational, long term value creation (instead of irrational, short-term value extraction), we might all benefit more.

This part I'll be disagreeing. Technology leads society leads technology, ad infinitum. The tech is making those being "rational" lose out too much, it's hard to tell people to change and there are no signs of users following what is considered the better course of action for the long-term. So the tech needs to enable profit-maximisation behaviour in better directions, which I think could be fixed as per the proposal. I think traf's explanations are very good here and it actually changed my mind. Like if Steem's econs is actually the equivalent of flying too close or too far away from the sun, then we're just fighting against all odds to make things work. Traf may not be making such an irrational move after all, since it's a problem that will likely be woken up to and addressed eventually at some point for a good dump, if the platform is still in public interest..

Maybe they are right. I still think much of the value we see here is because of people who choose not to exploit, even if given the opportunity to do so.

This is right of course, but doesn't address the problem. They're absolutely right.. what you've just said is almost equivalent as saying "it's okay, leak Steem's treasury to the worst behaviours on the platform.. it's okay, we moral upstanding people will take the hit until they go away.. somehow.."

Again, those taking a stand is currently getting "taxed" by the worst behaviours on the platform. On equal grounds, if SP accumulation points per month for those taking a stand and actually contributing to the network is only +100 points / month, while those exploiting are getting +1000 points / month. In 10 months, the difference is 9000 points. This is the chasm we're facing at the moment.. and good news is that it can likely be fixed, as proposed.