So I'm taking this dualclassed ranger/cleric trough the series with Tutu. Her stats were:
Str: 18/94
Con: 16
Dex: 16
Int: 12
Wis: 18
Cha: 15
Right now I'm somewhere in Durlag's Tower and I have already found some tomes and her wisdom is currently 20, and I've heard there's another wisdom tome to be found.
So I'd like to know if such a high wisdom gives you any bonusspells or others extras. If not, I'd like to change her stats in ShadowKeeper and lower her wisdom a bit to get her dexterity up. Thanks alot.

The only significance is that your lore will jump again, and you will get a bonus 3rd and 5th level spell, instead of a bonus 2nd and 4th.

So having 21 in wisdom isn't really worth it? I'll relocate some points then. Thanks.

It's not instead, it combined with all the bonusses you got before.