You are totally right that market cap is a horrible metric to "rank" cryptocurrencies, as it can be easily manipulated.
But the flawed rankings are caused partly because the ranking services (Coinmarketcap et al.) compare apples to bananas. Above all, because they compare complete blockchain projects with tokens which are created out of thin air, at almost no cost, on an existing blockchain.
For example, I would very much like a ranking service which compares only coins that have:
- an own blockchain (similar to the "Coin" table on CMC)
- no premine of any sort (this makes manipulation a lot more difficult, although it's still relatively easy to fake a market cap.)
This would make the ranking a whole lot more fairer. (If such a service exists, please post here

)
I for myself use even the flawed current ranking services somewhat, because they are basing their rankings, at least, on a kind of
hard fact. The things you mention, like "management", can be faked even easier than market cap. The problem is: as everybody can create a cryptocurrency and there are thousands of them, how do you separate useful currencies from hobbyist, get-rich-quick and scam projects? (Well, something like BitConnect was ranked pretty high for some time, and I also don't understand the Tron hype, but I think the CMC top-100 contain most useful currencies).