It's a pity that they don't pay more attention to the defaults.
I have been using Anki for Chinese with a premade deck (Spoonfed Chinese, if anyone is curious) for around 1.5 years and reviewing time has crept up too much. I have lowered the number of new cards per day several times (started at 20, now at 12, thinking about going to 10) but I am very averse to change the rest of the defaults since they are very technical things and it's hard for a layperson to know the optimal settings. I trust the Anki devs to have more data on, e.g., the typical rate at which we forget things than I, a random language learner, can have; what do I know about that? So I fear that changing something may harm my learning (currently I get more work than I would like, but I do learn).
You seem to know what you're talking about so I'll try your advice (thanks a lot for it!). But if any Anki dev is reading, please, pay attention to the defaults. I'm sure the overwhelming majority of users are going to use them, out of lack of information and/or fear of tweaking things that we don't know much about. It's a pity to have such an awesome software not live up to its potential due to bad defaults.
Would it be hard to ask the user a small questionnaire, like "how long are you planning to study this subject?", "do you have a specific goal (learning X cards by date Y)?" and "what is the average and maximum time you are willing to devote per day?", and use that to set reasonable options for that user?