I really like numbers and tables. Much more than texts, as those are clear, objective and easily comparable.
However my first point would require text, and that s an archive of the casinos current and past Term of Service and Bonus Terms and highlighting how often it changes and how. I heard of cases where someone won big with bonus balance, completed the wager and he was not allowed to withdraw it because on the fly the casinochanged the Bonus Terms to include the game he just played on as restricted slot. This would show how often does a casino do such things, which could be a strong red flag.
Shortened, understandable ToS, especially highlighting unfair points. (Though most offshore casinos have such unfair terms that this point might be totally irrelevant.)
For cryto casinos it would be nice to know which coins are accepted and on which network, also how much fee do they charge for withdrawals for each coin-network pair.
Again for crypto casinos: what currencies do they support and whether or not a player can change the currencies they play in anytime, or is it fixed at registration.
For fiat: list the different deposit and withdraw methods, and warn the player if there is such a deposit method that has no withdrawal option too.
Presenting the loyalty program, preferably with numbers included.
Presenting the various bonuses and their terms.
Making an indicator about how good a casino is rtpwise. Have a good rating if they licence the slots with the possible highest rtp, and lower and lower as they license it with worse and worse rtp. (Like how the same pragmatic play slots can be licensed with 96% rtp, or 94%, or even less. This is true for many other provider.)
Showing whether KYC can be done before the first deposit.
This is all I can think of right now, that I think most review sites lack.
This is truly a good amount of information that a beginner or even an experienced player should become familiar with.
However, I must point out, and what you also mentioned in your post, is the fact that casino regulations and customer requirements can be so variable, especially for casinos registered in offshore jurisdictions. It is simply impossible for a simple player without a legal education to understand these subtleties of the rules. And even with such an education, any lawyer will immediately discover a lot of all kinds of potential loopholes and inaccuracies in the rules. Unfortunately, all players constantly have to deal with sudden changes in the rules that do not improve the quality of their game at all. The reasons may be at the level of changes in the laws of a given jurisdiction and simply the creation of obstacles on the part of the casino to maximize profits and a change in managers or business owners, and so on. In general, in such legislative chaos, any player cannot realistically count on a fair and honest solution to his gaming situation in the event of problems with the casino.
And this, in my opinion, almost does not depend on whether the player went through KYC when opening a deposit, or whether he is required to undergo sudden KYC and in all similar cases.