I generally don't mind the evolution of S.P.A.M. having occasionally benefitted from a few of the slightly off-topic alerts (including one very recently) that I wouldn't otherwise have known about as well as discussion of MyPoints and such. If it truly turned into FatWallet Jr, I think it would be less useful. (Maybe it has done and I've just missed it over time because I visit it most times I check FT. Slow change, as you mentioned.) There's still a reasonable signal to noise. The example I had in mind was the REI sale, which is of course travel-related in that certain gear can be had there, although it doesn't quite fit for points/alternative miles.
I haven't paid close enough attention to see if there's post count padding going on, though. I only read threads if the title catches my attention. And perhaps I too quickly forget how many new threads are there which don't really catch my attention. And when I don't read them, I don't see how many are created by people with low post counts.
Not sure of the answer. I don't want to lose what's good about it, including some things that aren't quite points/alternative miles. But I do agree that it shouldn't be a breeding ground for those trying to subvert systems that are in place for other parts of FT and that we don't exactly need a FatWallet Jr forum. I guess the only real answer is heavier moderation. To me the topic doesn't lend itself to a post count/join date-restricted forum. We could send the freebie stuff to OMNI, although I don't think OMNI really wants it in most cases.

(I can see them now: "What's all this freebie crap doing in here?"

) The trick would be sorting what is good but sorta off topic (something like the REI sale thread, which in fact was initiated by a long-time member and has several long-time member responses) from what is truly pointless to post there. Although I guess it would be subjective. I just went back through the last couple hundred, and even the ones that only have one or two responses have at least 100 views generally.