Warbringer said:
That's the intent of Iron Heroes, to generate a completely different feel, with learning a whole new rule mechanic.
...at the same power level as 3e, so you can still use existing monsters.
That's a vital point. Iron Heroes doesn't throw out the CR/EL mechanic. Mike is to be commended for that. From what I've read, Mike didn't want too much of existing D&D abandoned when you use Iron Heroes.
However, because magic items are so much a core part of balancing D&D characters, the character side of things must be abandoned when playing Iron Heroes. That's fine. I'm sure many people will have a blast with it. (I tend to like magic too much

)
If Wizards had published this innovative product (and it's something that The Shaman brought up as innovative), then they would have drastically split their market.
The trick is to innovate whilst not destroying what has come before. I see this kind of innovation all the time from Wizards. However, when I bring up these innovations, the drastic innovation lobby don't consider them worth mentioning. "It's still D&D" is their catchcry. Well, yes. Isn't that the point?
Aside, how exactly does Incarnum plug right into Eberron, the now defacto setting (based on recently published books).
Ask Keith.

Personally, I use the Kosh explanation. "It has always been here".
For the most part, I envision Incarnum as using the normal magical energies. The one difference is that tapping into the souls (of aligned creatures or magical beasts) gives you the ability to shape magic as those creatures or beasts do.
The Eberron "Mark of Heroes" RPGA campaign allows Incarnum, incidentally.
Cheers!