I just started using the app and so far it is the ONLY journaling App that fits my needs without trying to lead me down other avenues not wanted. This feature is the one thing missing and i created an account to +1 this.
Even if we only support 2 or 3 levels of Indentation that would be helpful.
My mind thinks in a way that tries to break things down and dont always like to have all sub thoughts in one continuous paragraph, instead breaking them into sub bullets related to the parent theme. Indentation allows easier following of the sub thoughts and relationship between parent and child topics instead of having them all on one level with multiple parents.
One of the earlier comments indicating using different symbols for that, which i had not considered but this is kind of a workaround still.
That said, wanted to say, GREAT work on the app. GREAT work on making it single payment vs the subscription models, Keep up the good work.