My own impression is that high Wis does help land communes.

Certainly when I played drow shaman people regularly commented that I landed supps on them much more easily than other people.

Or is possible though that that was because I was choosing supps that they find harder to defend against. Eg plague and poison Vs low con races.

Int is quite important though if you are a shaman as it affects how fast you regen mana. As a druid you will regen fast anyway.