I don't know the game inside out to mod it myself (or spoil what's out there by finding and modding it) and balance it right, it's not just an XP thing but also the actual challenge of the battles given your own party will remain at the same numbers (and with added xp power) yet deal with less enemies etc., I doubt it's as easy as say, reducing enemies to half but doubling their power and xp. If you've modded it appropriately so it's not a cakewalk but maintains a challenge and difficulty curve good for you but I think it's a bit much to ask from the average user to do so, especially if they've not played/finished the game or did so aeons ago to know what and how to mod it appropriately. I'll check out the forge thing for the other enhancements but it doesn't seem like the solution outside the theoretical possibility of it.
I guess I don't understand exactly what you're looking for then. You said you wanted to speed up combat and there's definitely easy mods for that. I would sincerely recommend against INCREASING enemy power. The game is already supremely balanced. It's just hard and demands player investment. If you are having a lot of trouble with the duration of battles consider more casters or hybrids. Even rangers get access to AOE spells that can help if you train them properly. Many enemies can hit hard and fast but don't have much health so a good low level water spell from your ranger can take quite a few out.
Honestly my biggest tip to make the game easier is get the two amulets of endurance from the temple in arnika. They're invisible so you need either a ranger or to be actively SEARCHing. Stamina is arguably one of the most important stats in the game. Everything costs stamina. Walking, running, spells, attacking, and defending. The worst possible scenario is your front line guys run out of stamina and become literally unable to defend themselves. Once a character loses all of their stamina they'll faint and become completely defenseless. All bonuses from armor, skills, etc are gone.
The game is a constant war of attrition between gaining and losing your HP/MP/SP. The game's biggest fault is its poor pacing outside of combat. You often blow all of your magic in a fight to try to get through it quick enough you don't get overwhelmed while your shitty priest or bishop desperately heals one person at a time for like 20HP. Now as soon as you get out of combat you have to camp to regenerate all that. A bard really helps. The instruments they can use are essentially free spells.
Here's a quick rundown of my tips to maybe enjoy the game more.
Create your party with 2 melee, 1 ranged, and 3 support characters. There are plenty of recruitable characters to patch any holes.
You CAN change classes during level up provided that you have high enough stats to make the change.
Consider the benefits of various class and race combinations. Faeries are physically weak but have extra MP regen and start with a weapon that has a 50% chance to put the enemy to sleep on contact. And we already know how dangerous it is to be unconscious. You can give those to your fighters to put in their main or offhand to really give yourself an edge.
Dump skill points into attack skills for your main fighters
Focus hard on training magic for all other classes even if they can't use it yet.
Pick one or two stats and aggressively pursue getting them to 100 to unlock the respective advanced stat skill.
Amulets of endurance for your main melee
GRIND! There are simply not enough enemies in the first area to prepare you adequately for the first open area. Without actively pursuing battles, your characters won't have had the opportunity to develop their offensive and defensive skills appropriately.
Learn the keys for last action, use item, etc. combat doesn't have to be a slog.
Wizardry 8 is a careful, methodical game that really demands careful consideration from its players. Class, skills, positioning, stat management. It's a lot. But seeing yourself grow from weak little babbies to extremely powerful and steam rolling everything is really rewarding.
Edit: bonus tip: take advantage of the terrain. Lure enemies into advantageous positions and back yourself into tight corners limiting how much they can flank or get behind you. If they spot you first and start combat consider walking or running to the nearest V shape corner in the landscape.