I would be totally against post value capping, for many of the reasons you mention. I'm not sure if this is actually viable or not, but as a minnow who is still trying to break through the challenge of low visibility and therefore low numbers of valuable upvotes, one tweak I would propose is to allocate a certain amount of the Steem being produced to be a kind of base pay for content posted. It would not be huge, but it would be guaranteed. So you know going in that if you post something here, you will get some kind of small reward. Then if your post is popular with the whales, you get the additional rewards, kind of like a commission, and that's where the real wealth potential is.

Having proposed this, I am aware that implementation would come with lots of challenges around keeping fraud and plain junk down to a minimum. I have some ideas for addressing this, but that would make for a much longer comment.

Ultimately no system is going to be perfect or please everyone, so you really have to pick your system and stick with it, maybe tweaking it a little here and a little there. People will adapt and make the most of just about any type of reward arrangement provided it's consistent. Under the current system, people (myself included) are largely trying to boost their potential profitability by networking and gaining followers who will at least see their content in their feeds. Most of my current followers are probably also minnows, but that is OK, because today's minnows will be tomorrow's whales, so it's money in the bank.

I like the idea of making Steemit more fun by gamification. You could potentially reserve some Steem Power rewards for people who successfully complete "missions" that would also serve to educate them about your vision for Steemit.

I think there's a lot of potential here, and a lot of creativity. In making tweaks to improve things, please keep in mind that what we have now is already amazing.