StakePool Metadata registries are already mentioned in the delegation design specifications (Section 4.2)
Based on this back in Feb-2020 I wrote down some thoughts and ideas on a Cardano decentralised stake pool registry.
This mainly concerns existing pool tickers. Either those from the ITN phase, or a reputation built up over a longer period of time in the Mainnet. What if someone then simply registers the same ticker again to collect delegations of incautious users ?
Not allowing ticker duplicates always implicit some sort of centralization (An entity or person can permanently control/block a certain “piece”)
This brings up the question of how wallets, delegations centers, explorers, apps, … can identify and show (sort, filter, block, highlight) the right ticker. How it is possible to prevent adversaries to create a mess in the Cardano Stake-delegation user interfaces or at least to filter it out afterwards?
Looking at the earliest registration date (first reg win) is not useful because one can simply quck register with an acceptable amount of TX fees all known and a lot of probably useful tickers without using it at all.
This brings us directly to a second idea: use the lifetime stake (sum of all epoch stake) or the total number of produced blocks by a certain poolID / Ticker. This is a direct and pure technical indicator allowing the delegation centers to decide which pool deserves a prominent place and which one might a “possible fraud” badge.
Next question is if there is a risk shortly after genesis when all pools start from zero, for attempts to take over existing tickers and their reputations by unknown players. To prevent this we would need some mechanism or verified dataset allowing the wallet in the early stages to know who is the real pool ticker.
Metadata registries can be part of such a solution. To start for example a Cardano Foundation Registry can provide a reliable source, linking all known ITN pool-IDs with the new mainnet chain registration.
Subsequently, however, it can become an interesting additional task for several independent registries to enrich the Cardano ecosystem and to provide several decision criteria in the wallet delegation centers, the pool explorer portals and mobile apps.