I can tell you for world moderns that PCGS has basically not changed at all. I put through around 30 world coins and every single one graded at or better than I was expecting. For Japanese meiji and Chinese (Republic and modern) issues - I am just putting through a couple of batches of 20 coins and will let you know if there is a change but I really don't expect them to have especially for the meijis - right now there is almost a half grade average between PCGS and NGC for meiji coin grading (PCGS is the more conservative) and so I don't expect PCGS to get any stricter.
Of course this is to be expected as CAC currently do NOT grade world coins of any sort as far as I am aware, however its a good benchmark for comparing with changes in the morgan and other us spaces.