Other way around actually. Bitstreaming involves taking the audio track off the disc and streaming it out, bit for bit (processing the stream is left for whatever is connected by HDMI). Consequently, bitstreaming takes less "work" than decoding.
Only LG knows if they'll ever decode DTS-HD. Obviously it would be a welcome addition, but I wouldn't count on it. BTW, decoding DTS-HD is a more intensive process than decoding Dolby TrueHD (as has been discussed in other threads).