I agree. However, I think people would use it on radicals, which is their prerogative but may be inappropriate if you use them for mnemonics. That would get the kanji faster if you could use it on radicals but have the problem of bypassing the premise of the lessons. Early on one should try the radicals at least to see how the product works. So the way in which content is structured and unlocked presents an issue for testing out.
I think the slowness is not really a problem in the greater scheme of things because there are other things to study. But I don’t think people’s ability to use the SRS properly would be warped by being able to mark 一 as a known kanji. (Of course, kanji unlocks are tied to radicals and levelling to a kanji threshold, so it would only really be useful if you know most of them in a level.)
The thing about the free levels though is they’re a really good way of sampling the lessons, even known material.
Generally: I think getting personal is inappropriate. And the reality is some people can go faster than WK, investing great amounts of time and effort into RtK or their own decks etc. It’s equally arrogant to think that because the design is this way for a reason, people are presumptuous to question it. WK is set at a medium for its target demographic. It is not an arbitrary medium but it still obviously can’t be ideal for everyone. And still others won’t understand. That’s okay.
In general, the pile ons in these threads are more hostile to new users than the unintuitiveness of SRS (or the lesson structure), imo. Nobody is making anyone repeat themselves to these threads. Just move on if you don’t wish to provide unpaid customer support, which is your right. Someone will explain and the discussion can be had again.