[3.5] Max HP and current HP increase saving thows

[Ceaon]

I am thinking of a system where creatures who have a high maximum HP and creatures that have a lot of HP remaining gain a bonus on saving throws. This increases the need to damage creatures before unleashing powerful abilities or spells that require saves, which in turn upgrades martial classes and blaster mages.

It's still very much in the pre-planning stage, but to give you an idea:

Example values
Maximum HP 1-25 means a +0 to saves
Maximum HP 25-50 means a +1 to saves
Maximum HP 51-100 means a +2 to saves
Maximum HP 101-200 means a +3 to saves
Maximum HP 201+ means a +4 to saves

Current HP >75% means a +3 to all saves
Current HP >50% means a +2 to all saves
Current HP >25% means a +1 to all saves
Current HP 0-25% means a +0 to all saves

Before I continue with this idea, I'd like to hear the potential problems with a system like this that the Playground can come up with.

[D-naras]

It makes Constitution even more important but at the same time AC is upgraded because you want max hp all the time for the +3 to all saves. Blaster mages still deal with saves, they just get to do half damage on a successful save. Though, this allows a mage to blast once or twice before laying down the SoDs. I like it.

[Just to Browse]

A few things will happen:
Defensive buff spells are even a higher priority, and casters are still crapping on melee but are also playing padded sumo with each other.
No-save-just-die spells (e.g. blinding spittle) are more highly valued but just as rare, so the noticeably high-op casters are even more overpowered relative to their plebian counterparts.
If implementing the first possibility:
No caster actually cares because the HP scaling means most foes will have at most a +2, but if you increase the HP then high-HP foes can start breaking the RNG with their save bonuses.
Players will have 3 new categories on their character sheet where they divide by 4 and multiply by 1-3. Functional, but not ideal. Also the bonuses are small enough that casters might only deal ~25% of the target's HP before tossing SoDs.

This doesn't really help martial characters (spells are still better, just with a different priority) or blasters (ER still bones them, blasting spells still suck and use save rules to deal damage), but it makes the game a lot more interesting. And I love interesting things.

Personally, I would integrate 3 thresholds into the game, but each would have to be easy to calculate and the save bonuses would be a much bigger deal. Something like:
> Above 50%: +4
> Above 10%: +2
Dividing things in half is pretty easy, and taking 10% of something involves shifting a decimal.

There's a very obvious cutoff, which can be stacked up to break the RNG when above 50% HP, but going below that lets caster chance skyrocket so giving them big guns is more OK. Taking a target below 10% HP generally isn't worthwhile, but if you really need to take a dude prisoner you still have a reason to keep your fighters around.

[Kazy]

Is the idea to 'just buff' or to 'represent reality'?
If it's the latter, how about working this idea the other way around. Instead of a bonus to saving throws while being at full HP they recieve penalties according to their missing health.

[Ceaon]

The idea is to increase several things:
- importance of damage dealing
- usefulness of in-combat healing
- difficulty of using save-or-die/suck spells
- the amount of times saving throws succeed
Realism isn't really a factor for me.