It's not unreasonable to have an IDE that requires capabilities similar to its target.
Visual Studio on a PC, compiling x86 and x64 and god knows what other extensions you're targeting (or the whole ARM ecosystem just as well), working within a bazillion frameworks, languages* and dialects, doing graphical interfaces, doing internal and inter-process and inter-network message passing, building APIs and frameworks from the ground up yourself (not just using those others have made), the list goes on.
*Okay, I don't know if VS does languages other than C/C++/C#. I'm guessing there may be a few blobs of other languages spread about Windows and other M$ products. I'd further guess they use VS all the same, though maybe with plugins to better support other languages (or custom scripts or..), rather than out-of-the-box functionality. No idea, I don't work at M$...
I can excuse something that has to do all those things, and takes up a few gigs. While the average user isn't going to even begin to scratch the surface of the true power, the wide breadth of features available (and, inevitably, the painful obscurity of the bugs in all of them), I can accept that, okay, it's made for the worst case, tallest enterprise, expert coders, while still having nice enough features that the ordinary coder isn't overwhelmed.
I can accept that.
But five gigs for an 8-bit micro? There can't possibly be anything that needs that much information, data, code, to support something so simple. That's practically enough data to map out every possible state of the platform and write provably-complete programs with (heh, given that the time required to evaluate those proofs may not exist in this universe). Even including XMEGA, AVR32 and ARM, all the combinations and types of peripherals, all the extensions and variants, all the descriptors for those should total a couple of megs. GCC knows most of these things (that is, only to the level it needs, not to some imaginary extreme case) and does it all in a few dozen megs.
The sheer fact that you're running a graphical IDE, with rich features, code inspection tools, all the usual nice things, I can accept that that takes a few hundred megs (of storage or RAM, usually both). That's true regardless of target platform. When you want that level of richness of capability, and structuring, there's a price to be paid. Likely it's not actually that high (did anyone make a modern-featured IDE back in the 90s, say, running in DOS/Win/*nix, that took up only a couple megs?), but most of what you're paying, at that point, is dealing with the OS you're running on (which often takes a few megs just to get started with anything at all), and providing pleasing graphics (which can consume a hundred megs easily, for high res, low compression graphics).
Basically, you're paying for the convenience of coding on your personal supercomputer. Being a supercomputer, it takes a lot of code to do much of anything, no matter how simple it is; and for not much more work, we can use a rich system that makes our job easier, whether writing for such simple platforms as AVR, or otherwise.
I can accept that.
But driving a simple platform from an enterprise-grade system?
That just don't make no fuckin' sense.
Tim