All the currently discovered game mechanics can be found on bg-wiki and wiki, it's not like dmg not affecting attack is not being discovered yet. Also which MMORPG or even single player RPG you played have dev tells players every single game mechanics in game? Most of them are still found by players, or posted on the forums that you have to research for it.
This isn't about specific mechanics...its about really basic information on character statistics. In actuality many other MMOs have tooltips on weapons, stats and other info that tell you how much an increase in strength or agility or what have you will increase your attack power, and in some cases it even outputs DPS for you in the stat window.

FFXI's still stuck in the Everquest design philosophy in telling the players basically nothing about how the game works. It worked a lot better in incredibly flexible/open-ended games like UO but for such a PvE-focused game it just makes the game really inaccessible to new players. Long-time players might get irritated by people like OP, but it's certainly understandable why someone wouldn't understand how something as "basic" as D rating and attack works, because it isn't really intuitive at all.

Though the OP's attitude of "I know what I'm doing!" when he clearly doesn't isn't going to encourage anybody to help him learn. =P