Look here donkey, no it isnt.
There is a time and a place for NOE's and when its used correctley will and has dispersed the hordes that are defending or attacking bases.
You stated that you saw NOE's regurlarly in the EW, cant speak for that. But they are used in the LW and are defended against by some known adversaries. I rarely see 25-30 guys in NOE's much less that many in the EW arena, more often than not they are 10=15 in an NOE.
Either way they can be defended against. You dont have to sit in a tower to wait for a blinking base, you can still fly and keep an eye, or in your case an ear, on the game.