Yesterday I had almost finished with changing reflection before shifting over to party play.

As proof of concept, I have set the following rules:

• Non-sentient objects (walls, doors, etc.) with "can_reflect_*" will always reflect spells. Non-sentient objects without reflection will only reflect lightning.
• Monsters have a 60% chance of reflecting, if they have "can_reflect_*" set.
• Players have a +20% chance to reflect per item they have equipped with "can_reflect_*".
• Multiple reflective objects on the same tile stack, so a player with 20% reflect standing atop a player with 80% reflect will result in 100% reflection on that tile.
• Walking into a spell/missile with 100% reflect will still result in taking damage, the same as currently.

These numbers (and the system as a whole) are subject to change - please post any feedback here.

The strongest and most common interaction on spellcaster mobs and the reflect happens when you are low level at the SG cemetery, at mid levels in DT and at high levels in GT and The Pit in MV, all the other situations in most times won't be heavily affected, now these changes will affect most negatively the low levels as getting hit from a magic bullet or projectiles can mean insta kill, at mid levels it can be a little harsh on farming (mostly in DT) and on high levels the ammount of projectiles are quite few since the screen will almost be full of storms, overall affecting mostly low level to mid gameplay IMO.

Now the variation on the reflect percentage on mobs helps most the priests and low level mages since they can just switch to storms, priests can switch to Hallowed Ground but I believe this spell requires lvl 90 and by that point you could be considered high level, it's an improvement nonetheless, I personally appreciate the change as it will improve the low level player playthrough.

About the reflect spells 20% per stack, I would consider getting it at least to 50% percent considering the low level players as it can turn fatal in most times, but the subsequent instances shouldn't be added through a direct sum of them, I would make it somewhat exponential so it never becomes 100% and trivializes gameplay, I would go like this:
1. 50%
2. 70%
3. 80%
4. 85%
5. 88%
6 and on. 90%

Just as far as how reflect works it's current a flag where it's either set on or off on an item. So without a major rework of reflect it's not possible to have varying levels of reflect on items. Having said that miopol's suggestion of variable effects of stacks isn't hard to implement so should be doable.

It was mentioned that in future enchanting items could be possible with reflect being one of them. As an interesting thought would another good stat to have be something like spell penetration (probably needs a better name!) that would have the effect of removing a reflect stack.

Some good points brought up here.

I'm definitely concerned about low-level players - mob spells are very deadly at low levels, even after the small nerf added a year ago. I like the idea of reflection being a damage reduction source for this reason, although in this case I think reflect items are pretty rare for LLP's (assuming they didn't get a free ammy from another player). Perhaps one or two sources of easy-to-acquire reflect items for LLP's would be in order.

If reflect evolves into a form of damage reduction, I think either imposing a cap or introducing a "spell penetration" like Shroud suggests would be in order. Players ignoring spells is probably a bad spot for the game to be in. I think Chroma's solution here may be ideal - essentially replicating how resists currently work, such that it's impossible to achieve immunity unless you have an item with 100% resistance.

Probably at low levels if you include more reflect items the game will be an either you wear them or you die, taking away player agency.

Enchanting will help mostly high level players with currency to enchant, considering low level players I would add spell reduction as another stat altogether and included in gear, maybe connected to Spell Failure?, it's expected if you go as a bulk of armor a firebolt is gonna hurt, but if your gear has magic properties imbued they should protect against magic (just an idea).

The idea (I think) is to make player decisions important, and have variety in the gameplay.

I have replaced reflection on amulets with deflection, which is calculated by: RANDOM_ROLL(10, level / 3)

This means mobs level 1 through 32 can drop 10% deflection, and at 33 and above will drop randomly between 10% and (level / 3)% for a maximum of 42% (mobs can be up to level 127). Additionally, low and minor shielding amulets have both castable and missile deflection and the camp drop rate for low shielding amulets has been increased.

Cloaks, bracers, and shields can also drop with up to 28% deflection.