Does Duolingo plan to do grammar exercises?
I think some (more) grammar explanation (not necessarily excersises) would be great. Some things in French grammar appear inconsistant or unpredictable. I'm sure there are plenty of books about that on the market but would appreciate it if it were explained here. Maybe under a "help" button?
Definitely. They may be not as you imagine, but in fact, you always do grammar exercises here. You don't always get explanations before you do the lessons, but during the lessons you have to figure out the grammar or look it up elsewhere; otherwise you'll just fail to complete the lesson. I don't know if you have already gotten to different cases in German. When you do, you'll drill those articles really well, and this will be done not by doing special article exercises, but just by translating sentences. You will have to know when to say "der Tisch", when "dem Tisch" and when "den Tisch". When you translate a simple sentence like "A girl is putting a book on the table", you not only learn (or review) the words for "girl", "put", "book" and "table", but also learn (or review) the correct verb conjugation for 3rd person singular, the correct preposition and the correct case of "table" for languages that have cases. So, can you really say you are not doing grammar exercises? ;-)
As for grammar introductions, the team is constantly working on it. Those tips that you can see now in German were not there before and they are still missing for more advanced lessons. Now you get tips about cases and genders right in the lessons which was not possible before either.
I took German as an example; other languages may be a little different, but I'm sure they are heading in the same direction, too. French may take more time because there is only one language expert there (Rémy) while there are two for German (Julika and Myra).