Nikon D7100 will kill Panasonic GH3

There should be no doubt that the D7100 will be an excellent camera.  Being the second generation product that is improving on a really nice D7000, it should help to stop some people switching to M43 and be a star this year for Nikon.  In particular, it will mean big trouble for Canon's DSLRs, if Canon still cannot come up with sensors that are competitive, if Nikon gets more DSLR market share as a result in what is a shinking market.  I therfore Canon has more to fear.

I believe the D7100 will be, with most lenses, still noticeably bigger and heavier than the GH3, and size and weight are the main reason people switch to M43.  The other real advantage that GH3 has over the D7100 is its video taking features, but not everyone needs or want to pay for them.  An enhanced IQ in the D7100 will definitely make the difference in IQ between these cameras clearer than previously.  So, it is not wrong to say that there will be an impact to the GH3 sales, but I don't think GH3 will be killed.  May be maimed, given its high price and its bigger size and weight (not that much smaller than D7100).  Expect a drop in GH3 price when the D7100 is on the market.  E-M5 will be affected too, but to a lesser extent, as it is in comparson to the D7100 clearly smaller, cheaper, and has a special feature that most would find useful and value (unlike the video in GH3), i.e. its 5-axis IBIS.