I think +2 from the high ground is a bit too much, considering that it stacks with lightning charges, happy, bless and so on. Making it +1 instead would be a good thing to do.
With the recent addition of weapon actions, spells with a saving throw got an indirect buff. A lot of weapon actions can inflict a ST disadvantage on a target, making you very likely to succeed. Also casting bane before the battle greatly increases your chances to land a spell with a ST. When I build a character around such spells, I try to get Bane spell for my Gale and Wyll and gloves of the absolute power to my Laezel or Astarion. You can opt your playstyle to make great use out of those spells, but in general I agree that they could use a slight buff in comparison to attack roll spells.
