See, I think L.E.G.I.O.N. is selling as much as it deserves, if not more. If I had my way, it'd have been cancelled ten years ago along with the rest of the ill-conceived 90s spinoffs and tie-ins. Why? It's a good book with fresh stories that you haven't seen a million times before. Yes, it even has aliens that doesn't look human or humanoid (look up a Gil'Dishpan in an old LoSH book). But you aren't reading it, are you? If I were to nitpick, the book is called R.E.B.E.L.S. and I hardly think you can call it a "90's spinoff" since before the retitling during Zero Hour, it had been published since 1988. Points for trying though ;)
The logical conclusion is that the commenters here don't hate every single thing that came out of the Silver Age. My take is that scans daily likes to bitch, and are slamming the writing team for bringing back the 70's to go on to moan about how much better comics were when Young Justice was being published, and Batgirl was Cassandra Cain, and Ted Kord was Blue Beetle! It just seems very hypocritical to whine about this kind of thing when at least 75% of scans daily would spontaneously ejaculate if DC announced a Young Justice series, or Cassandra Cain as Batgirl - you know, it's not "writers being lazy" that is the issue as "the writing team aren't bringing back the characters we want them to bring back". Fan entitlement.
Scans Daily likes a lot of Silver Age motifs, ideas, and yes, even characters.
They don't like modern characters with more upwards of a decade of development being killed, tossed aside, or ignored to bring those older characters back.
Some times, because they liked those Silver Age motifs or ideas, they -also- don't want a particular character to come back because...they died a good death/went out with a bang/deserve their rest. I don't believe this for a second. Bart Allen and Conner Kent both went out heroically, but scans daily peed it's collective pants with joy when they came back. My take is that it's all about fanboy (or fangirl) entitlement issues. That said, as long as you aren't buying books like R.E.B.E.L.S. or Blue Beetle that offer a fresh take on old characters (and are well-written to boot), you're convincing DC to stick with the tried and true characters - e.g. Barry Allen and Hal Jordan over Wally West and Kyle Rayner. I think I wrote this before, but you're not getting the comics you want - you're getting the comics you deserve.