Seems flavorful and imo def not overpowered. All this multiclassing to do cool things is mostly a trap anyways. Most of the time multiclassing doesn't make the character anymore powerful, just able to do a specific thing that people want to do with their character. The widely considered best multiclass pal2/sorc x even has serious issues, if you paly first then you have much slower spell progression, and at any point below lvl 17 you lose spell progression, and imo any good gm with properly spaced encounters will show a smite happy smiter that these spell slot are probably better used to cast actual spells.