Bitmain's quality control is so poor and the process to get something fixed is so bad that it really is hard to justify continuing to spend money with them.
I think its simply down to the DC circuitry design. Bitmain uses a serial DC circuit. It's very efficient, but any single failure in the circuitry results in the loss of the whole board.
So if Bitmain wants to improve the L3 how about improving the quality control and making a reliable miner. Not one that is going to get hotter, louder, and most likely be even more unreliable than the current L3's. If this plays out the way it sounds I don't think I will be buying any of the L3+.
Clearly they can't or won't. They've had at least 7 or more generations of miners now and they all seem to have the same serial DC circuit design/manufacturing flaws. My guess is that if you're Bitmain and can access new boards nearby at cost, the reliability trade-off relative to the efficiency is a good trade-off.
If on the other hand you're several thousand miles away and have to pay retail prices and operate through a re-seller, then that trade-off is probably totally unacceptable. Buyer beware. Based on their illustrious track record I certainly won't be buying any Bitmain products.