There are several issues here, and it might be well to distinguish them:
1) Keyword stuffing on site: most people who do things like this and ask questions like this are concerned about the search engines. And they ought to be: it is a dangerous thing to do. But we aren't experts on that, and prefer to defer to the experts.
2) Keyword stuffing in suggested descriptions in ODP submittals is ... too common to remark on. Editors are responsible for the final wording, and we just delete the whole description and start from scratch. Not a problem, since that's what we'd have done anyway if we found the site through any other mechanism. But this does not appear to be what you are asking about.
3) Keyword stuffing on the website, from a surfer's standpoint (and here's where we come in, since we edit from surfers' standpoints.) And here it depends on the surfer's intelligence. People without severe mental handicaps can tell when they're being keyword-spammed. (Now, many sites target stupid people, and so they don't think this is a problem. Usually, these sites don't have unique content anyway, so we don't worry about the keyword spamming either--we just reject for cause.)
The problem only arises in the very rare case where a site has unique content but still uses the idiot-salesman approach. And in these cases, editors may be predisposed by experience to suspect these sites of having no unique content, to look harder for evidence of that, to be quicker to accept proof of having some non-unique content as evidence of having no unique content, and to delay site listing until that suspicion has been fully assuaged -- which may be a VERY long time.
But a webmaster would really be irrational to worry about that!
Why?
The editor isn't going to buy anything anyway. It's the non-brain-dead surfer who's going to be buying -- AND THEY WILL REACT THE SAME WAY! (Editors are, after all, merely surfers on busman's holiday.)
So if you are doing the keyword-spam-in-syntactically-correct-blather gig ("widgets are great! many different companies supply widgets, so that you can get them from many places, cheap. Here we have links to places where you can buy cheap widgets...."), then you should be worrying -- not about us, but about surfers in general.
Now, the next question is "I'm a marketroid by birth and training. How can I tell whether a real human will think my carefully-constructed persuasive marketing copywriting sounds like syntactically-correct-hype-whiz?"
This is really, I think, where you are: and it is a very difficult question. (I see it from the other side of the linguistic spectrum: I frequently get a reaction from marketroids that "your [information] isn't persuasive, isn't emotive, isn't ... in short, isn't all sorts of things it isn't intended to be." And I really can't tell whether it is any of those things, because what I was interested in was simply communicating information. Whether someone else WANTS to be informed, or whether they could have been persuaded by emotional lies when the truth wouldn't serve, ... well, I can't answer that, and I don't try. But you may not feel you have the analogous luxury.)
I somewhat diffidently suggest this as an approach: pretend you are an infrequent visitor to a site, in a tearing hurry to get to some information you know is there (but don't remember how to find.) If downloading and skipping past the keyword-stuffed-hype-and-blather delays you more than five seconds, then, Houston, you have a problem. And if you're a competent professional web designer, you'll already know you should be aiming for under three seconds.
If you aren't that competent, do the best you can. We see a lot of amateur sites (for that matter, we're amateur site reviewers!) and we'll be tolerant of people who at least make their attempts to go in the right direction. If your site navigation works well, we'll skip past a lot of inane blather to get to the content -- if not, and we skip a lot of blather without seeing the content, then you may be toast. But again, real surfers will be carbonizing your surfaces with the same exothermic oxidation reactions.
