I am not a lore master, nor have I played PnP D&D, but I wanted to talk a moment about what I have learned about the Artificer class. If I am wrong, or otherwise inaccurately describe an aspect of the class, I welcome any corrections.
Dont go getting all puffed up on me about Druids (I still want them too!) but I think the artificer class would be easier to implement in DDO than Druids. Why? Because we basically already have them!
What is an artificer?
For the completely unaware, there is a decent entry in Wikipedia. Basically you could say they are the pure class form of the popular multiclass Wiz/Rog. They combine the trap skills of a rogue, and the arcane skills of a wiz. However, they are not casters, in the true sense (like a Wiz/Sorc or a cleric/FS). An artificer "casts" magic by storing charges of a spell in an item, and them releasing them in combat. Their primary skill would be UMD, So you could say an Artificer is like an arcane rogue for Eberron.
Given their association with crafting, and their tendency to work for House Cannith, Artificers tend to be very good with items, weapons, and constructs. Like was said before, they can infuse spells into equipment for later use (it is actually called "infusions"). They are also naturally skilled with disabling traps, UMD, and opening locks (dont worry rogues, stealth and sneak attacks are not their specialty). They also have item crafting skills. For example, they gain the ability to craft/repair wands, potions, rods, staves, magic weps and armor, and rings as they level up. They can also harvest the magic essence from items to use later.
Obviously Artificers are the creators of constructs, and they built the WF we know today. Their knowledge of those allow them to create, repair, and obliterate constructs with ease. They also have the ability to craft Intelligent weapons (as was discussed in a different thread, I wont go there, it was a lengthy issue).
You said we already had them?
As you can see from the description, many aspects of Artificers already exist in the game in one form or another. It might take some work to mold those aspects into a single class, but theoretically it would be simpler to do it with what already exists than it would be to build a new class (druids for example) from almost nothing. There is something to be said for building a class from scratch, but building from existing elements has advantages as well. Unfortunately for Artificer and Druid fans alike, Fernando Paiz has already implied they plan to implement another race after Half Orc before they start with another class. Then again, that was months ago, so who knows.
Allow me to illustrate an artificer in combat with the words of the great Keith Baker:
WARNING! May contain spoilers. Do not read if you wish to read The City of Towers: The Dreaming Dark Book I
(note: unarmed combat was required by the Minotaur for the challenge)
Lei turned and bowed to the Minotaur. It watched her, its inhuman expression impossible to read. Handing the darkwood staff to Pierce, Lei ran her fingers along the studs of her armor, murmuring quietly, then she produced a pinch of powdered stone from her pouch and rubbed it into the leather of her belt. Daine recognized the mystical significance of her actions, but he had no idea what enchantments she was weaving into her clothing
After a few minutes, Lei's preparations were complete. She turned and walked toward the minotaur, pausing at the bottom of the steps. She stood straight and tall, her arms at her sides, and took one slow, deep breath.
"I wish to talk to the wind," she said.
The guardian nodded, then without warning he charged down the steps, a blur of black and gold.
To the others, the minotaur might be moving with blinding speed. But Lei had prepared for the fight, and to her enchanted eyes the beast was like a bull charging through three feet of mud. She barely moved, slipping just beyond his reach and turning as he rumbled past.
The minotaur turned to face her, and Lei raised her left hand. With a whispered word she activated the power stored in her glove, and a dark bolt lanced out to strike her foe. Shadows wreathed the minotaur, blue light tracing his muscles as the magic leached the energy from his sinews. But the minotaur was already in motion, and he slammed into Lei before she could slip out of the way. The golden studs of Lei's armor flared with light, and the shimmering field of translucent energy deflected much of the raw force of the blow - but the sheer momentum of the attack threw her to the ground.
Lei cursed as she struggled to her feet.
She hadn't hurt the minotaur, but she had weakened him, and he was acting with more caution. They circled for a moment, then Lei slipped forward and past him, coming up behind and planting a powerful kick where she thought his kidneys might be. But if the minotaur felt pain, he didnt show it, and Lei had left herself open with the attack. Grunting, the beast slapped her with a powerful backhand blow. Her enchanted armor kept her on her feet, but for a moment the world went black, and when her vision cleared a monstrous fist was flying toward her face. Calling on every ounce of will, Lei dropped beneath the blow and slipped forward. Bringing her right hand up against her opponents chest, she extended her mind, reaching into the glove and unlocking the power she'd bound within. The minotaur howled as a brilliant arc of electrical energy surged through his body. The beast dropped to his knees and offered no resistance as Lei put her foot his throat and pushed him to the ground.
The smell of ozone and burned fur filled the air, and for a moment the only sound was the minotaurs labored breathing. Finally, he opened his eyes and looked at her.
"You may enter," he said. There was a distant click, and the door to the temple swung open a few inches.
As you can see, there are things that are already in game that can mimic the way an artificer is played. For example, there are already augment slots in armor that can be used to store charged enhancements. I'm not saying its true to PnP, but DDO is modified, after all.