I wear diapers for their utility. My primary concern is effectiveness, that is, the absence of leaks over time. On another thread, one about how it feels to be diapered, I noted that the bulk is part of the experience and see how it's a necessary part if the diapers are going to be used as intended.
I simply do not see how an effective and secure diaper cannot be bulky. The need for bulk and the desire for discretion create a conflicted set of priorities for both the diaper user and the diaper makers. For me the choice is bulk over style.