Re: CDMA ?
" 4G (OFDM) and 3G (CDMA) drains the battery, just as switching between 3G and 2G (GSM) "
Andrew could have been referring to WCDMA (UMTS/European) or CDMA2000 (American) or just the multiplexing method CDMA. Its pretty ambiguous as he uses the terms interchangeably but in any case, he's still correct.
I think what's key is that the operators get a grip on when to allow the device to connect to LTE and when its better to keep it on 3G. For example receiving a lot of text messages/calls (at say around once every few minutes) will kill the battery unless the network utilizes an efficient timer (on when the device is next allowed to search for a faster/higher priority technology). Of course that'll be somewhat alleviated when they finally get around to using VOLTE (Voice over LTE) or similar.