I've shot my 7D2 for around two years now (professionally for photo and video), and have never been disappointed with IQ.
Autofocus paired with a good lens is phenomenal. Shutter speed works wonders for action stuff.
The only time you'd notice a different in bokeh/ IQ/ richness is if you're comparing a shot from the 7D2 against a newer FF camera.
You probably already have some L-series gear for the 5D2 (which will no doubt produce good results on an APSC sensor), but you should consider buying some crop lenses if you do invest in the 7D2. I have the Sigma 18-35 f/1.8 (best lens I've ever used, produces better results than L-series), and Tokina 11-20 f/2.8. Since these lenses are: 1.) High quality glass 2.) Made for crop sensor they have unbelievable IQ. That being said, I use my Canon 70200 f/2.8L for all tele stuff, which also produces amazing results.
This video helps explain the FF lenses on crop sensors.
My website (
leocorralesmedia.com) has dozens of photos all shot on 7D2, with all three of my lenses. If you have any more questions about video, ISO performance, etc. Feel free to ask.