I think it would be great to have a scraper node application process: Fulfill these X criteria to become a candidate scraper.

One thing not covered in the discussion was geographic and hardware diversity for scraper nodes. Im sure you realise why having all scapers on AWS in the USA (for example) would be a bad idea; if AWS or the USA was offline for some time then no superblocks would occur. Clearly this isnt as serious as blockchain fullnode diversity, but 5 scrapers feels a little on the light side to me.

I think an enhancement may be to use what you described as the DPoS type thinking, where if we had more validated scrapers, a simple round robin cycle could be used. Perhaps the maximum we should have is 25 to prevent BOINC projects feel like they are being DDoSed, and if we have 50 vailated scrapers we just take turns in who provides the consensus for each SB.

I would probably happily operate a scraper node, Im not the most active in the community, but I've been around Gridcoin since Classic days, and a BOINCer for over a decade.