Its got terrain warning, traffic alert (when mode 'S' is implemented across europe), contoured moving map, auto ILS alignment and storm scope to name a few features I would call extra functionality over a standard modern IFR fit.
You can have all of this if you have a big GPS or an MFD.
The question is the cost.
Honeywell GPWS was £13k when I looked at it a few months ago; I believe Garmin are doing something (in the form of a "certified" obstacle database) on the GNS530 for a lot less but I don't think it is a comparable product since it doesn't deliver avoidance warnings with aircraft performance accounted for. (It's a ripoff price of course; the function could be incorporated in a £200 GPS from a camping shop).
The full installed TCAD can be had from about £12k, last time I looked. The installation cost is significant; the plane has to be nearly taken apart to fit the various aerials and cabling (I've seen it done).
A WX500 stormscope is relatively cheap, about £2000.
None of the above are new in any way, and plenty of pilots have all of it. Just turn up at any moderately competent avionics shop (if you can find one...) and they will be Absolutely Delighted SIR to help you
The question is whether a G1000 delivers the functionality for a much lower installed cost.
Remember you also need an ADF and DME - with the G1000 these need to be remote reading units, to do it properly.
I don't think we are there yet, in both integration and evidence of long term reliability (both hardware and software). A few years to go, IMHO.