7 is not a bad number perhaps as it is essentially 1/3. it means significant control but not enough to have 50% majority and far enough from a super majority.
I would personally also consider spreading the rewards at a higher level to the 20-40 slots. I am not sure what the spread is now but if 75% went to top20 and 25% distributed on it might incentivise differently. Have to think more on that one though.
1/3 seems like a good idea to me, at first thought.
Having less witness votes increases the risk of people just going for the most popular witnesses. Meaning: you, @blocktrades are obviously someone who brings a lot of value and stability to Steem. So my vote for you is pretty much clear.
And the fact that I have 30 votes, means that I can also vote for some more experimental witnesses, who might not have proven themselves so much, but still need support.
If I'd have only 7 votes or even 20 - I'd have to weigh down removing your vote and voting someone else, multiple times (depending on how low the total votes are)
You may be right that lowering it to 7 votes would concentrate the votes to fewer witnesses, but I'm far from sure that would be the result.
But regardless of whether that's true or not, I think the important thing is to increase the security level of the system against an attacker who suddenly obtained a large stake (e.g. hacks an exchange that has a lot of steem). As far as I can tell, limiting it to 1/3 of the top 20 would dramatically increase the difficulty of such an attack (for example, all things being equal, the attacker would probably need twice as much stake to gain control of the chain).
If the issue is funding for development, I actually think the chain would be better served by a worker proposal system like the one that BitShares has, as opposed to the on-again-off-again idea that witnesses should be developers/marketers/etc. Conflation of the primary task of witnesses (block production) versus other "work for the blockchain" potentially leads to poorer block producers and poorer developers/marketers by excluding better candidates for each task as a witness must be good at both in the current system.
Sorry to bud in, but I can't help myself...
I always thought this was super reasonable, and yes I know that a certain someone proposing budgets made most of us cringe, but I think for the most part we let our biases get the best of us and I mean that respectfully.
It makes perfect sense that the chain's stake holders would want to decentralize development too. I mean, many of us can talk until we are blue in the face about how much better Steemit Inc could do, but there is no reason why development for this blockchain has to come strictly from them.
I would love for other big stake holders to weigh in on this. It looks like a win/ win situation.
I'm pretty sure it's not on steemit's roadmap, so it would take another dev team to incorporate it I think. I doubt that will happen in the short term, but it's definitely possible in a year or so.
I'm with you that the security of the chain should be priority number 1°! That's why I don't find it acceptable when a TOP witness is being run by other witnesses or if the concentration is on a few specific hosting providers. Not saying that they can be bought, but single point of failures should be avoided as much as possible.
So maybe it's a discussion worth having.
But regardless of that outcome, worker proposals are actually something which might be game-changing for Steem. Is there a specific implementation you have in mind?
The one used by BitShares is pretty good, IMO, although a Steem one should include the option to be paid in SBD as well as Steem I think.
Also, note that a concentration of votes on fewer witnesses would also increase the difficulty of launching an attack on existing witnesses with a stolen stake.
Very smart!!!