Is the accumulator a passive item that always regenerates energy 'in the background', or something you can equip?
The main way to balance Predator would be to limit his energy availability. Make Plasma Caster consume at least 100 energy points per shot minimum, Plasma Blaster that depletes at least 20 EP per shot, slow down energy regeneration considerably, add a delay between any time the energy supply gets reduced and when its recharge starts. Also, Cloak should use much more energy per second. And maybe add energy consumption for special vision modes.
Regarding the weapons, it is a good idea to have Predator start only with Wristblades, since even those are quite powerful. Speargun is super powerful, it feels like a subtle rocket launcher in terms of damage, and has plenty of ammo laying around. Likewise, the Plasma Blaster is pretty much a Plasmagun, and uses next to no energy to fire! Very close to EZ mode. And of course there is a Plasma Caster with seeking projectiles... but since it is Predator's counterpart to BFG, it is justified.
(I have a lot of other notes, but I have to double-check them, so I will post them sometime later, maybe in another day)
- The accumulator is the staff-like device the predator use to refil the energy supply.
- Most of your points about the energy management have been adressed already. The regeneration rate of the energy is now extremely low and is only increased with boosters that are now even more rare than in 1.3(and will completely dissapear if the honnor system is approved by the voters at the poll). Also no more free ammo for the speargun and mini-missile launcher because as i said before the only way the predator will gain ammo and weapons will be by killing other predators and even so it's not a guarantied drop. As for the Plasma Blaster using 20 EP it's not a viable energy consumating rate because it will make the weapon almost useless because, among other things, it's the weakest weapon of the predator in term of damage dealt per shot. To counter balance i would have to increase the damage per shot and i don't want this weapon to be OP like the Plasma Caster. It would have be a good thing with the old energy management but with the new one it's not an option.
- If you played any of the AvP games and some of the standalone games like Concrete Jungle the cloak isn't consuming that much energy. In fact it's the least consuming device in term of energy and since this mod is vastly inspired by the AvP 2 game for the energy management it won't be a good thing to accelerate the energy the cloak uses per second. Furthermore in AvP 2010 the energy the clock consume is practically non-existant.
- Having the vision modes consume energy is something i had done before and i had removed for practicallity reasons but it's not impossible i bring it back for tactical reasons. I might have to start a poll for this one because i'm sure some would not want this to be back while others like you would want it back.
- About the speargun being OP : In all AvP games the speargun was featured it was capable to kill almost any enemies with 1 or 2 shots except for the hard-skinned enemies like the Queen. Even the synthetics could be killed with one shot if aimed at the head(in AvP 2 the head gets ripped off the body and pinned to the nearest wall, that's how powerful that weapon is) and now that there is no more ammo spawning on the ground for it the occasions to use it would be more strategic. Also unlike the 1.3 version the 2.0 while being a bit more powerful no longer has it's damage multiplied by the boosters and no longer has it's maximun ammo increased by grabing a backpack is is constantly limited to 50 ammo and never more that 50 - the backpack is exclusively used by the Marine class now - in fact everything that is spawning on the map (with the only exception of the ally beacon) can only be grabbed by the Marine class.
Well, I am still not sure about Praetorian's Booster. For Predator it restores energy and health, and also gives a damage multiplier. For Marine, it refills health along with armour. But when playing as Alien, the Booster makes you unkillable! It feels like you got a permanent invulnerability (even your health bar is frozen)! Is it supposed to be this way, or is it another bug?
- You still can be killed if you take too much damage by being attacked by 1 or 2 predators. The only effect of the boosters on the Praetorian in term of health is it accelerate the natural health regeneration and of course the more boosters the faster the health regeneration is. However in 2.0 it's been drastically changed because as i mentioned before the boosters are really rare now and the likeliness to gather enough boosters in one map to be invincible is practically non-existant and if the Predator's honnor system is approved a similar system would be implimented for the Praetorian and will be usable on-demand - in fact it's still in testing and will be ready for full implimentation if the poll is positive.
- The damage multiplier is more reasonable for the Predator because in 2.0 it will only affect melee weapons(blades and combi-stick and melee attack of the smart disc) instead of having an effect on all weapons.