I did read the whole thread, and no, I did not see anyone provide an answer for the battery drain problem. If this specific issue of ICS draining battery life has been addressed & answered somewhere else, then I would really appreciate if someone could either just repeat the answer or provided a link to the solution in this thread. I have searched these forums & googled this issue, but no I have not found a fix for the specific problem that I am experiencing.
SO yes, I would very much appreciate a solution or a link to these other threads.
In terms of switching between 3G & 4G & data off, I would recommend this really great app called Llama that can trigger switches between mobile data states and wifi automatically after user-customizable conditions are met. Llama can also automate a lot of other battery saving actions and it is 100% free, so it is definitely a good power app to check out. The difference in battery life with 3G & 4G simply depends on your 4G coverage & signal strength of the area. If you have weak 4G coverage, then 4G will drain a lot more battery life, but there shouldn't be a drop in battery life after upgrading to ICS.
However, if there is a bug with let's say "Exchange Services" in the new ICS keeping your device from going into deep sleep, it doesn't matter if you are 3G/4G/Wifi... you are going to lose a lot of battery life. From my experience prior to the ICS update, I could get 15-20 hours using Wifi. Now, I am down to 6-8 hours regardless of whether I have Wifi (with data off), 3G, or 4G enabled. After disabling "Exchange Services," my battery life increased to 10 hours. I am now currently trying to find the other battery drainers that activate wakelocks & prevent my device from going into deep sleep to increase my battery life back up to 15-20 hours.
So, if you think that LTE On/Off is the "solution" to increased battery drain after upgrading software..... then, I really don't know what to tell you.....