Is stemming somewhere on your todo list?
For example, a document containing the single word ‘drawing’
isn’t currently found, even for a fuzzy search, for the word ‘draw’.

Stemming is quite difficult because this requires language dependent analysis or dictionaries (and DEVONthink is currently language independent and hopefully will always remain).

However, using the "Phrase" option, DT will search for substrings too and therefore "draw" will deliver results containing "drawing" of course too.

And a final note - we’ve actually been playing with some ideas in the past solving this problem without using language dependent solutions and our approach did improve search, classify & see also results a lot but unfortunately this needs LOTS of CPU power. Anyway, we will probably introduce this feature in the Enterprise Edition (and in other editions if we’re able to optimize this or when average machines will become faster).