Over the past 5 years, I know both UA and AA have raised the redemption levels but they are within tolerable range - between 5K to 10K in the most part, except the UA to Australia, which went from a very undervalued 90K to 120K to now 135K in J. UA gave 6 months notice when it changed the level from 90K to 120K (on South Pacific alone). When it did a systemwide increase, again it gave 6 months notice.

AA modified the rules of OneWorld award on how to calculate the distance traveled from a Beeline format to an actual miles flown format, largely because the abuse of redemption - people redeemed for Beeline 20K miles flown as calculated, but actually flew like 40K miles with convoluted routing so they could experience J and F cabins as much as possible... It is of little wonder AA finally changed the rules.

The bigger devaluation is in the area of Upgrade award - it went from miles only to miles with co-payments and the co-payments keep going up - that is where it hurts those who mainly fly cheap tickets to maintain their status but use miles to upgrade so the flying is more comfortable.

Of course, taxes and fees used to be absorbed by the airlines but that was may be well over a decade ago... So you can call that a devaluation as well. I remember AA used to have a hotel discount certificate as well as a car rental free day certificate when redeemed a flight award, and it absorbed the taxes and fees.

So the devaluation is there, but the degree is different in each individual's eyes largely depends on What do you use your miles for. For us, the devaluation is tolerable so we use them as we need them but do not deliberately burn them. In fact, for the off peak season between Europe and East Coast, we are willing to sit at coach, albeit in exit row, for 20K one-way rather than 50K business class when it is daylight flight. However, for the 14+ hours to Asia, no way we would claim coach awards. So we use miles the way we see fit, and feel comfortable having 7 figures combined balances.