For lower level magic and an S&S grittiness to the game a fast fix that works well is to do the following;
1. Reduce HP dice for PC classes to one-step lower (e.g. 1d8 becomes 1d6, 1d12 becomes 1d10 etc.)
2. Make all healing spells use up the healing HD of the target (or in emergencies the caster) on a 1 HD for each slot level of the spell basis (life force is burned to fuel magical healing...)
3. Make Paladins the Clerics (but they can access Cleric Spell List); Make Rangers the Druids (but they can access Druid Spell List) and the only 'full' caster the Warlock renamed as Sorceror or Mage with the following changes;
(a) Replace all but the 6th level Mystic Arcanum with an Eldritch Invocation
(b) Add Arcane Tradition of choice from the Wizard Class (now called 'Path of Mastery')
(c) Rename 'Otherworldly Patron' to 'Eldritch Bloodline' (the casters source of power)
(d) Rename 'Pact' to 'Arcanum' and the character gets Chain
and Book variants
(e) Make Intelligence the spellcasting stat
(f) Use the Your Spellbook rules for the Wizard Class, this otherwise being the Book from the Warlock Pact
(g) Use Wizard Class Cantrip and Spells Known progression
(h) Use Wizard and Warlock Spell Lists
(i) Has Font of Magic like Sorcerer Class
(j) Remove Eldritch Blast from the game but allow all relevant Eldritch Invocations to apply to all damaging Cantrips
4. No Bards or Bear Totem Barbarians.
5. All magic items move up one step on the rarity table, so Legendary Items are considered artefacts.
6. Introduce 'Mastercrafted' items which either give +1 DR per class (lt/med/hvy) for armour, +1 AC for shields, +1 damage for weapons or +2 skill for tools.
A nice balanced 'low-mid' magic game will ensue

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