I'm probably going to take the general consensus on the conjugations, and slowly (there's not too many of them, really) move over the helper verbs terms that have completely different meanings (like 持って来る) into a new term, and leave ones like 知っている.
As for people giving suggestions - this is normal, and I can't really fault users for not saying anything. I used to run a site that had 200 times the number of daily users and the feedback was still extremely low when it comes to actually discussing bugs, etc. It's a mix of two things: difficulty of reporting (I get many more error reports from the quizzes because you can click a button, write one sentence, and be done with it) than I get from a thread like this (you have to step away from what you're doing, read at least a few paragraphs [my post], maybe everyone else's, then give an answer that's probably going to be longer than shorter)
, and just ...indifference. I'm guilty of the same thing, I have no doubt you are, and everyone else has had times like this. Most people don't visualize the person/people behind a website, I think. So, if there's a small problem, unless it completely obstructs you doing what you really want/need to do, you (as a user) are probably more likely to just ignore it than think you need to contact someone behind the site and ask them to fix it.
or (just thought of this one) - people also see sites as huge things with tons of users. If you have a problem, you might think 'this is probably common, so I'm sure one of the other tens of thousands of users has mentioned something', so you don't need to. I've lost count over the years where I'd get a message that reported a not-so-small error that had been around for awhile, but when it finally got reported, the user would say "I'm sure you've already gotten a hundred reports on this, but...".
They feel like they need to apologize for reporting the bug and taking up my time, which is backwards, since finding bugs helps me do my job to improve the site.
In short, there's lots of reasons that people don't comment/report, and they all make sense, so that's just the way things are. :)