I might give some feedback as well, even though the question was not pointed at me, if I may.
Imho the whole advantage of LingQ is that it speeds up a process that would have worked 50 years ago, too, but would have taken much more time. Reading through texts, looking up words you don’t know, is an approach even my mother used 20+ years ago to teach herself Greece. She bought greece newspapers at the main station and spent half the sunday translating the articles. Obviously, looking words up in a printed paper dictionary is somewhat time consuming.
When it comes to LingQ the impression one can get at first is that the whole process of creating the definitions is super important. I think it isn’t. A definition doesn’t have to be perfect, it can even be wrong as you can correct it later on anyways if you stumble over it again. And if you don’t, it doesn’t matter if it is wrong. If you start to spend too much time per word looking it up, or if you try to add all the grammatical nuances of a specific word into the definition, you just waste time and the effect of LingQ - speeding up the look up process - gets destroyed.
I personally turned on the ‘pages move to known’ feature after having it turned of for a long time, and use LingQ in combination with the Google Dictionary plugin as well as (the super useful) Yomitan plugin on browser. I create definitions for a few forms of a word, but not for all, use the existing definition or the ai definitions (sometimes deleting parts of the latter if it includes other parts of the sentence) as much as possible so I don’t have to type (despite beeing a somewhat fast typer).
There is no fixed rule, but I always try to outweight the amount of definitions created with the amount of time needed. If I create too much definitions, I waste time. If I create too less definitions, I may be in the need to use the dictionary too often, repeatedly looking up the same word, which wastes time, too. With Yomutan and Google Dictionary, the latter is less of a problem, though.
Obviously this approach can be problematic for those who want to use the LingQ Spaced Repetition feature or who care a lot about the stats.
Another aspect is that it would be good to encourage new users to import content for learning and advice them how to do that. You should always work under the assumption that your customers never have tought themselves a language before or never attented a language school. I assume there are a lot of new users who are already on the older side and may had their last contact with language learning in school. So they are probably a bit lost. If you throw a guide at them in a language they are about to start learning, it isn’t useful either.
You can see it in comments made here in the past, that some users assume that the app will provide them with texts they can read. Beeing more informative on ways of how the app can be used or how it is intented by the designers might be helpful. I described one way that works for me, and that is, of course, shaped by the specific characteristics of the languages I learn. Others may use it quiet differently. And the way it is designed might differ, too.