Since I've found a local friend to go in with and save on shipping, I'm a tad happier about buying online only.
I picked up Wave 4 at a K-Mart locally, which gave me some extras. That was the last wave I saw, and I saw remnants (repacks) of it once I believe at a Wal-Mart but none of the new(er) figures were there. Just the Wave 2 Luke and the Star Wars Vader were all I saw (well, Vader's newer I guess).
I never saw Malgus wave, anywhere, but in the case I got.... This wave seemed to have been seriously stunted. Acxtually Wave two with the DS figuers seemed stunted too, come to think of it. I only saw it, or remnants, 2 or 3 times IIRC. Part of me honestly thinks Hasbro saw the writing on the wall, and that 2 waves deep with TPM repacks was a big mistake, and they didn't let many of these out of the gate if they could.
Wave 4 SEEMED to hit more... Not here, but other areas seemed to see it semi-frequently, at least relatively speaking anyway.
Wave 5 I've barely heard a whisper of people finding it at all really.
Wave 6... maybe it's a turning point? Probably not.
From what I've seen, most retailers have their re-order points set to basically the pegs being bare. Target it seems pretty solidified since people clear the pegs, and then a re-order takes place at some point. WM it's more difficult to say for sure. K-Mart, at least here, hasn't had a ton on the pegs since the year began... Actually, most of mine didn't order Wave 1, which has been to their benefit. I've seen more new Clone Wars there than anything. The only TPM figures I saw at K-Mart were from the Deleted Scene wave's repacks.