I believe this is due to market tactics , this is all up to Verizon network to enable/disable glance screen , similarly what apple did with my iPad - I own an iPad 3 which has apple based A5X dual core chipset with 1gb ram and retina display , when ios 7 came in beta version it has all the transparent effects which made ios 7 feel , looks different , but in the final beta 5 they removed all the effects and made it look ugly, grey-black, now lets compare with this iPad 2 same A% chip (iPad 3 does have A5 chip but the X means it has quad core graphics meaning more powerful than iPad 2 ) and iPad 2 have 512 MB ram , making iPad 3 more powerful , iPad 2 did get all the effects in beta but were removed in final build , iPad 4 which is newer model get all these effects , now lastly iPhone 4s , which has the same A5 chip (found on iPad 2 and iPad 3 ) with 512 MB ram get all the effects are transparency of ios 7 :0 , shame , ipad mini 1st gen have the same specs of iPad 2 but it got all the features of ios 7 including airdrop which was exclusive to newer models
now what I did in ios 7.0.4 , I installed cydia on it via evasi()n tool , with some tweaks I got all the effects of ios 7 including air drop which they said will not work on older devices due to hardware.
Verizon is doing the same , they still want to sell Lumia 928