If you want completely unrestricted options and to bypass some of the odd combat design choices in the Pillars series, this is the definitive mod to download immediately.
There are a ton of changes here, but most notably, you get to access 8th- and 9th-tier abilities for your multiclass characters when you reach higher levels (which is unbalancing, but very satisfying), all the Berath's Blessings abilities only cost 1 point, and -- best of all -- combat abilities and potions can now be used outside of combat.
If there was one mechanic preventing Pillars of Eternity from fully evoking the feel of the classic Infinity Engine games, it was the inability to cast spells and ready yourself with potions before the fighting starts. That issue is entirely negated with this mod, which makes it a must-download. Now you can have your summoned creatures and Iron Skill spells already fired off so you are more prepared for any given battle.