Frankly, I find this whole change underwhelming. Sure it is a devaluation for some people, but then it will also give a lot of people on more expensive eco tickets (especially domestic or European short-haul) a lot more (40%-60% for me personally) miles than before.
Also please remember that at least for German/Austrian/Swiss customers, it is much easier to accrue a ton of miles via cheap magazine subscriptions (eg. currently there is an offer for 60,000 and a daily newspaper for a year for about 700€). To get the same amount of miles with flying, you will need to spend 10 times the amount of money. So I am not sure that giving away award miles is that much of a concern at LH at all.