Just one more idea to lengthen combat/saves/damage pvp battles.
Introduce group saves.
1. Each group will have max skills and spells for "group saves". Solo players will be treated as a group of 1. For example, if a group has shaman, warrior and red robe, they will have the max axe weapon from warrior, stupefy skill from shaman, concentration from red robe (a few examples).
2. Each damage skill/spell will make "additional" roll against group saves.
a. Weapon damage will be rolled against group saves and damage deducted if saved.
b. Similarly spells/skills would be rolled against group saves and damage/effect deducted if saved.
Here is a melee and spell example.
Locki (with superb axe) and Cyren (with spell harm/blind) is fighting Erika (ocean wielding axes) and Kaput (another cleric).
Erika went 6X melee on Cyren (with annilhate dam per melee).
Since Locki has a higher superb axe skill than Erika, after the group save, Erika 6X extreme on Cyren.
Kaput sunray on the same round.
Since Cyren has the spell "blind", Locki gets a bonus save against sunray (but fails anyway since he sucked).
Skill example.
A group with a shaman will have better chance of saving against an enemy stupefy.
Similarly a group with black robe will have better chance of saving against nightmare.
Same thing goes to entangle/ice storm type.
Group save: Spell
There will be greater chance of saving against spells if your group has the same spell. Else, partial save will be added if the caster has the "slot" for the spell. Ie, a group with a black robe with 9th circle will get partial group save against enemy nightmare. A robe from a different path will get less group saves.
1. same spell: group save at 50%
2. same slot (no spell) same class/robe: group save 25%
3. same slot different robe: 15%
4. no same class/robe: 0%
Group save: Melee/Skill
The group save against skill would be dependent on type of skills. If it is damage based, then like melee, there will be damage and "miss" chance. If it is effect type, then there will be duration reduction and save bonus.
1. Group melee type higher: group save at 50%
2. Group melee type same to 20% lower: group save at 25%
3. Group melee type lower than 20%: group save 5%
So, if you bring a variety of classes in your group to battle, chances of surviving is higher because most of the spells/skills/damage would be reduced considerably (assuming the group had skills trained higher than enemy).