I am having the same experience... I'm big on shortcuts and being able to maneuver quickly and efficiently. I mainly build network diagrams (L2 & L3) in large formats (ISO A1, A0) and I've found that using the SHIFT and CTRL keys combined with the mouse
wheel is very effective, however in 2013 it loads so slow that it defeats the purpose.
I imagine this has something to do with how 2013 is caching the data. I read another thread that stated to disable hardware acceleration in the Advanced section of the Options in any Office app. I did this and while it does perform
slightly better now, its still not anywhere near how snappy Visio 2010 was.
Hoping for an answer/fix soon.
I'm sure this isn't a machine performance issue as both machines I use for diagramming are pretty powerful. One is an Alienware laptop (M14x) with an i7 2630QM and 4GB DDR3-1600 RAM with an NVIDIA GT 555M video adapter. My other is an i7 3770k with 16GB
DDR3-1600 RAM and an NVIDIA GTX 680 video card. Both are running Windows 8 x64 (RTM) with all updates installed, so the issue doesn't seem to be specific to Windows 7.
UPDATE: I have gained a slight performance boost by disabling the "Animate Controls and Elements inside Windows" option in System Properties > Advanced System Settings > Performance Settings. Still not quite on par with Visio 2010, but we're getting there.