Bizarre Internal Inconsistencies For No Apparent Reason

[worldofneil]

1) As a WHM when down-leveled to, say, 15 I don't have access to Stoneskin, but when down-leveled to ACN I DO have access to it - entirely illogical

As an arcanist you're using it as a cross-classed skill. They don't have the same restrictions as the base skills.

2) I CAN use my chocobo when doing normal leves but NOT when doing guildleves.

This is by design. They don't want us doing grand company leves in a party (which includes chocobos).

I mean, I don't mind restrictions but at least make them consistent and logical.

They are consistent though. Cross class skills don't have the same restrictions as base skills (a restriction) and no grand company leves allows being in a party (a restriction).