Having delay issues to the live feed back to the phone. Is it the phone (iPhone 4) or the quality set too high?

Even having problems with the app crashing and having to reopen midflight.

I've given up using the live feed generally and flying blind, or framing my shot with experience and not thru the phone.....any ideas guys?

Are you new to using the Phantom? The live feed won't be completely smooth and real time but should be close enough to frame a shot.
I think another user here lowered their frame rates.

The usual recommendation when there is a lot of interference  is to lower the Preview Quality to the lowest setting 320x240@15fps.  (The higher setting use a bit more bandwidth)  This does not affect what the camera is actually recording, only your preview of it.

I flew my Phantom 2Vision today, and never let it get more than 20 feet away (to maximize the signal-to-noise ratio), and the delay in the live video quickly built up to about a minute.  Preview resolution was set to 320/240@15fps.  Both the iphone 4 and 5 support wifi b/g/n, so one would think that either phone would support real-time video, huh?  Any suggestions?

I'm pretty sure that your problem is the iPhone 4. You are about 4 versions behind and quite frankly, you can't expect an app that processes video to work on such an old device. Here is a link that compares all the iPhones in terms of speed: http://mashable.com/2014/09/22/iphone-speed-test-all-models/

Definitely go for the upgrade on the iPhone. You won't be sorry. The faster speed is noticeable, and the TouchID / Apple Pay make it worth going for the 6.

Coincidentally, I just found the recommended devices in the Vision+ manual. Page 23 says 4S or newer.

May or may not apply to you, but the WiFi extender is directional.  Be sure to point the flat "top" of it toward the P2VP while flying.