I'm not sure if I understand the way how ARK tries to combat centralization risks.
Here's a quote from their
article on Medium:
User Kevin has 20 million tokens. Kevin can nominate his delegate fairly easily. He may even be able to vote in 2 of his own delegates, but rightfully so, he purchased 20 Million tokens. What he can’t do is be guaranteed to nominate more than 8 delegates before his weight is too diluted to maintain his position.
What makes Kevin's weight diluted before he can nominate the next 8 delegates? Can't he just create several accounts and spread his 20 million tokens between them?
I didn't find any clues on that in ARK's
whitepaper, just this:
The 51 forging nodes with the highest number of votes are eligible to Forge ARK
blocks. This design eliminates the possibility that any single large ARK holder or
an organization holding large percentages of ARK are able to gain control over
the entire network by voting for all of their nodes into forging positions, thus
effectively taking complete control over that DPoS Blockchain. Votes from ARK
Tokens held by ARK Crew may be used at ARK Crew's discretion.
I'm not too familiar with Arks specific structure, but 1 Ark represents 1 vote. Thus, it doesn't matter from which account someone voted, the voting weight stays the same. What the Kevin example tries to say, I guess, is, that if Kevin wants to use his Ark to vote his own delegate into a forging position, he shouldn't vote for too many other delegates, because then, his votes are spread over multiple delegates, lowering the overall approval, putting him at risk of losing his spot.
In Lisk, one account can vote for up to 101 delegates and for all of them, the voting weight stays the same. when I have 20 million Lisk, every of the 101 votes counts as 20 million Lisk. The Ark team sees a problem here, because in the Lisk system, big accounts are more likely to be king makers. In the above example, 20 million Lisk would be a little less than 20% of all existing Lisk. At the current level of approval of delegates, such an account could put 99 of 101 delegates in forging positions. Would Poloniex use their cold wallet to vote (currently holding 28 million Lisk), they could decide all 101 delegate spots, unless the rest of Lisk holders could come together to give even more approval to other delegats. The Ark team may have a point there.
You could create a hybrid between proof of membership and DPoS, where token holders can decide to give a token to an account. This account applies for a token, not so much in an auction way, but more in a social way, by somehow convincing those who already hold tokens, that it's a good idea to give them minting privileges.
By the way, I come back to the idea of the minting token either being something negative, to prevent users from hoarding them. For example, what if a newly created address would have a token at inception and only after a certain amount of blocks were forged, the token would be burned? The advantege could be lower fees or something along those lines.
I know, it's far away from proof of membership, just a thought