Same problem apple had it before with the ios 7! For some stupid reason they removed the 3G on button back then and now they are doing the same thing, and after a few weeks they released a patch to fix this! https://discussions.apple.com/thread/5325771
Back then people for over 2 months were forced to jailbreak and add third party from jailbreak apps to disable it!.
3G reduces the battery to more than 40% as apple was saying in gray letters under the enable button on 3G.
Carriers don't have complete coverage and most carriers have huge issues on antenna roaming voice over its antennas increasing exponentially the failed calls while moving!
Apple Solution is simple start reapplying Steve Jobs working methods so some people don't turn apple into the worse customer support and development company! They cannot keep repeating the same mistakes over and over again!
Repeating the same mistake while fixing it means someone is doing something EXTREMLY WRONG over at Apple! Or maybe Apple has not listening to its clients!
Maybe Apple will fix it as soon as it receive one of the probably biggest lawsuit against them for reducing the battery life into maybe more than half with the ios 8 upgrade!
I really hope apple will reintroduce the basic principle of development, as steve jobs did as definitely something is going wrong!! Its inexcusable to repeat same mistakes over and over again! Especially when you shamefully fix it in previous events! Or maybe new apple developers simple want to encourage people jailbreaking their phone so they can fix apples wrong doings!