I find the higher ranks a little bit empty in terms of unlocks, both for classes and skills...but I've come up with what I think is a very original class for DotD.
Basically, it would be the ultimate support class and...would be a little bit imbalanced when high level, but right now most games are played on nm I guess because hell is a little too hard...so that might be the class that would allow a team to get through it and would be almost useless for a smaller team.
Unit Name : Officer
Required Rank : MGen+
Armor type : whatever
Weapon type : Handgun (Beretta 92 a.k.a. M9, I guess), but other assault classes firearms can do as well
HP/Energie : low HP/high Energy, something like 200/350 at start
Skills :
Class Skill 1 : Some passive aura that would increase movement and attack speed (you know...efficiency and stuff). Now, I'm not sure if the Leadership skill already does movement speed, if it does I guess we'd need to replace that one or find something even more useful for the passive ability.
Class Skill 2 : Logistics command: that would allow the officer to request for logistical help, mostly gear: it would go from dropping items such as healing stuff, to ammo for primary and secondary as well and possibly dropping primary weapons, armors and other special items in the higher levels. (I think there's some BF command option that does something similar, I guess the skill would simply provide different items)
Class Skill 3 : Tactical command: the officer would request tactical support form HQ, that could be from a few units to a lot of additionnal units to artillery strikes to close air support (just like the medevac, except there's no evacuation and the helicopter follows the group...or say a Napalm strike where an helicopter [because we don't have a model for a bomber] flies by and drops a bomb that wrecks havoc on a HUGE area relatively close to the players => I think that would make an uber cool ultimate!!). What could also be added to tactical command is direct control of player's character for some period of time, a real officer is shouting orders, but since you can't really force a player to do something while typing in the chat then...you just take control of the guy. (it's just an idea, I don't think it's a great one, but it's certainly very different from anything else in the game!)
Class Skill 4 : A morale booster skill that would use mana over time. True morale (an esprit de corps, a cohesion between members of an unit as well as belief in the other's capacity) would be very hard to implement. Although, on the basis of the spirit walker's spirit link spell, I think it would add something interesting to the game. When morale boost is in effect, players would share damage (that's the basic effect of the spirit link) and possibly automatic stimpaks as long as they stay within a certain range of eachother. As the level increases, the duration could go up, cooldown drop, possibly add an effect or two to the basic "damage sharing" effect.
This skill could be easily exploited to tank a boss or something, that's why the distance the units must be apart from each other needs to be really small so that a boss can easily switch target once he started attacking a unit...and of course, when everybody starts to scatter, the morale booster does not work anymore.
And look! There's no crit skill! That would make him the most unique character around!
I know, it does look overpowered like that...but remember, it's the hardest unit to obtain and the first few levels would not be that great either. And really, in the end, it's all a matter of balance => the only way it can truly be overpowered is if we (or s3rius) don't balance him out correctly!
So, if we sum this up, I think we would have:
1- A cool new class.
2- A unit with useful skills at any difficulty level.
3- A cool new class.