How about this for a twist on making him better at Other Worlds, instead of the +1 to checks.
When Randolph Carter draws an Other World encounter card, he may always chose to resolve the Other encounter, rather than that of the location he drew.
I'm not sure if that's different enough from Gloria. It is, in essence, two encounters to choose from. I like the +1 to checks in OW.
Also, when it says "he is only devoured by Yog-Sothoth if he returns to LITAS" that could be confusing. Using the word "only" could mean that is the only way he can ever be devoured, or the only way he can ever be devoured against Yog-Sothoth. I know that isn't what you mean, but it could be interpreted that way. I would word it more like: "Randolph is only devoured by Yog-Sothoth's The Key and the Gate ability if he returns to Lost in Time and Space."
Otherwise, he's good. It's not surprising that RC was never used as an investigator in AH, as those are all made up, but it is a little surprising that he doesn't appear anywhere on an encounter or as an Ally or something.