I'm playing the 3.0.6. version and it looks like morgia root no longer trains WI. I am eating 4 blessed morgias and getting To increase as usual, but Wi remains the same (16, with potential 30).
Was it some recent change?
Edit: I had the boots of the far traveler equipped, which give a bonus to Wi. After i unequipped them, i started getting the Wi increases. It looks like a bug to me. If anyone else can test this (probably with any other Wi increasing item), to see if there's a need to post a bug report, it would be great.