I would be surprised to see any proposals being approved that are not by top witnesses. We won't and can't just give random strangers money and witnesses are the most well known people here, so that's just logical imo.
On the topic of top posts being by the same people - I am also annoyed by this. But on Hive I see two major reasons for it. First is that Hive is new and everything that once was posted on Steem needs to be posted here again, to build a new foundation. SEO-wise and to have those posts that help beginners. Second is, it's not any different on other platforms. On YouTube the same people are in the trends - again just a logical consequence imo.
If you only concentrate on posts it may seem centralized, but I think the times when Hive/Steem was a blogging blockchain are long gone. The amount of dApps and developers here is big, of course not as big as on Ethereum for example, but still dApps are being released on a weekly basis.
I think just the fact that we have no central company or CEO behind the blockchain makes us more decentralized than most other projects out there. It's comical if people speak about decenttalozation while 'their' blockchains have de facto CEO's.
And to be honest, I don't even see many options to make Hive more decentralized. Like, what could you even change? We have nodes, dApps, the supply is pretty well distributed. What could you change?
I think we should wait some more time and we will see how Hive will look then. For now I think we are on a good way, even though as I said above, some things are not perfect.