I suppose that depends what you define as the 'scope' of the protocol. The masternode network are simply peers of the regular network which operate in a an alternate logic mode. Thats why they're often referred to as a second 'tier', or 'tier 2'. Their function is 'protocol level' enough to be subject to the condition of mining majority for successful adoption which I think is the significant criteria in that respect.
As far as I know, it's impossible to have a cryptocoin which doesn't have public balances for addresses
Doesn't Cryptonote do that ? In Cryptonote the balances are not public.
Yup, I think they go only by transaction number? Or am I remembering incorrectly? It's a super confusing Blockchain explorer. I decided above all else, that cryptonote will likely never work because the amount of information each transaction has to be run through is going to become such a large database, it will slow down so badly that it will become a slug. I can't see how they can possibly trim any of it. They say they can, but I have other issues I can't figure out, and I've tried. Still,
no gui, a bloated block chain and no real developers working on it makes me think that if it's ever workable, it'll be 20 years in the future.
Being about 3/4 the age of Dash, almost 5 times the size blockchain, and far far fewer people using it (meaning not nearly as many transactions going through as Dash), their blockchain issues are massive.
Several CryptoNote coins also have an official GUI (and the others have unofficial GUIs) and development continues so your statements are false.