I can understand not bothering for short haul aircraft (e.g. 321s/737s) but I think that they should keep them for longer flights. All aircraft should at least have proper charging ports, even if it's just (or indeed, preferably) USB (which would cover all phones and tablets).
Personally, I just flew a bunch of flights in December (CA, KA, SQ) and didn't watch anything on the IFE besides the flight map. Flying domestically in China, I wish Air China would just leave the flight map channel on on their overhead screens rather than switching to whatever rubbish programs they put on. That plus finally letting people use their phones would solve the entertainment problems for me.