The point the OP makes about "HP based spells" being severely limited in their effectiveness is also worth stressing.
True, but HP based spells have been buffed - the static number is much better than rolling dice in my opinion.
However, I would like them to tweak the numbers of these spells, currently they are just slightly above the average roll (for example sleep first level 24 HP > 22.5 HP average 5d8 roll). An extra 1-2 HP would make them much more worth a prepared slot.