YOU may decide not to change. Again, I'm not some sort of WotC shill here. You may not like 4E. As it turns out, I do - not just as a system, but specifically as a system for Eberron. And that's the point of these posts: to explain why I think it actually works as well (or even better) for Eberron than 3E. The downsides are obvious; you can't use all the crunch from your old books, psionics won't be in place from day one, and who knows how quickly DDI will provide support for other unique features of the setting. So given that, why have I already jumped ship to the new system?
Last post I talked about the first basic principle: 4E embraces the idea that PCs are special. Action points are part of the core rules. PCs feel like tough and capable individuals from level one. NPCs follow their own rules; you don't have to have the bartender be a tenth level character just because you want him to have a good Insight score. All of this fits with my original idea of Eberron. It's easier to make a first-level character feel like Indiana Jones than it was before.
Point number two is one I have to approach with caution, because it's something that hasn't been fully revealed. And that's magic. The core, original idea of Eberron was that arcane magic was essentially a form of science - and that as a science, it ought to be incorporated into society over time and used to provide the basic services we've developed with technology: transportation, medicine, communication, entertainment, warfare, and so on. And we did the best we could, using dragonshard focus items and magewrights. The problem is that Vancian magic really doesn't lend itself to this principle. The concept is that the streets of the cities of Khorvaire are lit by continual flame. But when a magewright specializing in this spell can still only cast it once or twice a day, how many weeks will it take him to light Main Street? What does he do for the rest of the day after casting the spells? We just went ahead with it, saying that the most critical functions were provided by reusable magic items (like the Sivis speaking stones). But it wasn't really what I wanted - a world in which magewright could be a true occupation, not something where you could blow your professional specialty in five minutes.
Here's where I really can't reveal anything, because if someone official hasn't already explained how it works, I sure shouldn't be spilling the beans. However, I will say that the way non-combat magic (rituals) work creates a far stronger foundation for a magical economy than Vancian magic did. It's a system where it's clear how that lamplighter can put in a full day of work, as opposed to burning out his power with a single spell. So again, Eberron was founded on 3E, and the idea that magic was a force that followed logical patterns, that could be reliably controled by formula and ritual, and which could be taught - but Vancian magic always put some limits on the logic of a truly magical society. The rules for rituals make the idea of a professional, full-time magewright a simple and logical idea - and in fact, the system is such that it doesn't even require the existence of a separate magewright class.
More still to come!