[bhasi]

In my experience of having learnt Sanskrit via what I now realize is the comprehensive input method (thank you for introducing that term to me via your comments on this thread), I absolutely think that the "basics" - enough to recognize the seven (eight if you count the sambodhana) vibhaktis (declensions) and the simple past, present, future and the subjunctive tenses - are required in order to get past the huge roadblock of parsing a word.

Once parsed, I can look up the meaning of the word on ashtadhyayi.com or elsewhere, but not before.

[sieve]

Sanskrit grammar is complicated enough for basic knowledge of the cases and the tenses/aspects/moods to be less useful than one would otherwise assume. You have sati-saptami prayogas, krdantas are often uses as adjectives while basic text books talk about them in limited contexts. It is a huge mess.

Take this story (https://www.adhyeta.org.in/sa/k/samskrita-chandamama/198404/...). Assume you have a gloss available for some words. Do you really need to know the pratyayas for the nouns and verbs for you to be able to understand the story?

[bhasi]

I wasn't referring to knowledge of the Paninian sutras or pratyayas, to be clear, when I said "the basics".

For this story, you don't need to know the pratyayas but you do need to know the tenses, the ktva-lyap forms, etc to fully understand what is going on. With only an incomplete knowledge of those aspects, one can sort of intuit the overall meaning but eventually would find that they had the wrong idea altogether when reading the corresponding translation in a language they know.