I think a big part of the problems I am having is in how the graphics is working. Either QT is a very slow library (seems unlikely) or Fritzing is not using it effiently (very possible). I am running Fritzing on a Raspberry Pi, but using my laptop as a display using a SSH X11 tunnel. (And no, it is not the SSH X11 tunnel that is slow – I do the same thing with KiCAD, the Arduino IDE, JMRI, and other X11 programs and everything else runs fast enough. The Pi does have a 100mbit Ethernet and I have a GBit switch – the network is itself quite fast enough.)
And maybe it is the version I have on the 'Pi: 0.9.0 (it was what was in the repository for Raspbian).
Another problem for me is that I don’t have a good Internet connection at home – I am on dial-up (yes, really!), because that it all that is presently available where I live, here in Western Mass. In order to do any development work with Fritzing, I will have to sneaker-net about 11meg of .deb files (for the 'Pi – my x86_64 laptop is running CentOS 6 – the libraries, etc. are too old and yes, I need to update it, but again, that is a complicated process, complete with the complication of poor Internet connectiveity). Also , I have not done any GUI programming in C++ in a very long time and have never used QT before, so there will be a pile of learning there.