Sorry, too late and probably too lazy to sign up now to post on your forums but had a few comments/ideas about the stuff I read on there.
No save points in dungeons and experience/gold loss: My initial thought is that it won't work. No one will suffer the experience loss if they can simply restart from their last save and recover their exp/gold. An alternative to making death more impacting would be something like ditching the phoenix down type items for recovering lost allies and making players go back to town to revive them (old school Nintendo fun!) until maybe player mages have gotten strong enough to cast Life. (or make it more expensive: Phoenix down was always to cheap in rpg's: a miracle potion that can bring you to life and it's cheaper than a rusty dagger...)
Health/Magic going into battle: I'd caution about the resting/going into battle full health/magic thing that I read on there is a little troubling because it might make a dungeon feel like a bunch of repetitive battles than being seen as a whole experience. Basically if you can beat the toughest fight in the dungeon, you just have to do it so many times to beat the dungeon(if you can easily get full health/magic b4 battle) versus surving the dungeon as a whole (hope that makes sense).
The combo/skill system: I could see the combo system working in a few ways such as a attack/defense skill being counterattack and defense/support being protect (an ally) and maybe a combination of the two for an attack/defense/support skill that both protects and counterattacks. I think there might be a limit to how many combo skills could be come up w/ though.
Having specific levels for the skills: May be better to go with a mix like in Disgaea. Weapon specific skill levels were determined by how often you used a weapon and proficient you became in that weapon. However, major characters each had unique skills available only to them that they would gain at specific character levels or story points. Even if you just make all skills available at certain levels a player could still customize which skills their character is better at if they can strengthen skills by using them. Actually though, for now might just want to concentrate on making a simple attack system (or focusing on the basics) since I think issues like this would require a lot of playtesting and balancing(making sure some paths aren't too overpowered or others too weak).
The whole attack + defense skill lvls < 10 : Seems like this would be easier accomplished by choosing appropriate equipment and maybe the kind of back row/front row setup seen in some rpgs where the front row had higher attack and lower defense and the back row had lower attack and higher defense. Would definetly be annoying to work yourself into a corner where your character was having trouble getting past a point because his defense was too weak, or his attack wasn't strong enough, or his support wasn't enough to keep his allies alive.
Might be simpler to have multiple battle stances available for a character in battle and just let players switch those on the fly ( maybe one high in attack low in everything else(berzerk/blitzkrieg),a better defense/support one(sentry), another more balanced, and so on and so on, could even have these stances require players to search out teachers/instructors to teach em these new stance/fighting styles [though to be honest I don't know how excited players would be to just change numbers that they may or may not see a direct result of unless some skills(or maybe just a combination of skills) were unique to certain stances]) yeesh sorry run on sentence there....
Learning magic and skills: I kinda like the idea of people having to learn magic and maybe even skills from others/books/manuscripts(like in shenmeu, he'd learn new moves by finding ancient martial arts scrolls) rather than just "magically"/"intuitively" learning spells on the fly..."wow after that last battle I feel stronger somehow, I think I now understand the intricasies of tossing fireballs at my oppenents" [mage gains a level. mage learns Fireball 1.]
Concurrent Attack Limitations (CAL): I think a more realistic (but probably harder to program) limitation would be to have enemies respong to repeated techniques. Basically the more often you do a technique on the same enemy the less effective/unlikely it is to hit (probably based on the enemy and his abilities--a skilled swordsman will eventually learn to avoid/block/counter a strong technique the more often he sees it (kenshin vs saitoh[anime tie-in! yay!]) where a blob may never realize where that fireball that keeps hitting him is coming from)
yeesh think my post is getting too long so gonna cut it short here and get some rest