The Duolingo Japanese Course is lacking a lot.
From grammar to kanji, this course doesn't teach me enough. Will there be any more changes to this course?
The courses are constantly being improved upon. It's just a matter of having enough subject matter to warrant an update, I think. It takes time to create the pieces of a course and then it takes more time to integrate it into the existing material. Be patient, but also don't be afraid to seek out other resources. I use HelloTalk for Spanish language exchange. I bet you could find an exchange partner for Japanese willing to help you expand your base.
I wouldn't be so bothered by the fact it doesn't cover enough material if it covered the material it did more thoroughly. If you turn off "word bank" the course is almost useless, it marks you wrong on virtually every slight variation from the expected answer, including even just using kanji vs kana (yet bizarrely, accepts answers using hiragana where only katakana should be accepted)
Duolingo does have some pluses. Not having grammar explanations forces you to come up with your own. However, there are some that they should go over, and they will add in more explanations in due time. I remember coming across 何も a few times and not understanding what it meant. My idea of "also" (the も particle) + "what" (何) made zero sense. Eventually, I goggled that the addition of も causes question words to exclude or include everything. This explains why "what" (何; asking for a noun subject) turns into "nothing" when you add も. It also explained why いつも (always) comes from いつ (when).
Lingodeer does explain everything and helps out a lot, but you can always google your questions. And as someone said, they recently expanded their content to cover N4 material and hopefully, in the near future, N3. (They are making people pay for the higher level content as of the most recent update.)
The course continues to be developed, so you can expect it to improve slowly over time. In the last year, it has already come a long way, although there is much left to do.
In the meantime, I recommend LingoDeer as a similar program that offers much better grammar and kanji integration. It also recently came out with an extension that doubles the course length. It's a really nice app for Japanese learning.
If you're good at teaching yourself, doing the reverse course may be great for you! You can pick the English for Japanese speakers course, it covers what the Ja->En covers and way more! It will be bit more difficult of course, you will not be able to rely on Duolingo explaining to you.
Like others have mentioned it is in development. Duolingo is a helpful resource but should not be your only resource. You will want a grammar reference too and something to get some listening experience.
I also recently discovered that if you use Duolingo Plus for offline mode that the lessons will stop working offline once you "master" them. I can't tell if that is by design or a bug. In either case if you plan to learn offline you might want to eventually have an app that keeps the files needed stored locally.
especially with more picture-based associative learning so that it is not as heavily reliant on the english translations.
if anyone is looking for an app that is good at that i highly recommend drops, though its free version only allots you 5 minutes of practice every 10 hours.