Nokia has a strong community. But the biggest failure could be, they don't ask or doesn't matter. Their staff seems to use other devices or the N900 only in development environments.

Otherwise I have no explanations for Bugs like:
https://bugs.maemo.org/show_bug.cgi?id=5982 (The unlocked phone problem - never used the N900 as a all day phone? - on the desk I have no problems, too)

https://bugs.maemo.org/show_bug.cgi?id=10468 (they design different Keyboard layouts but make and test software only for those with 4 coursor keys)

https://bugs.maemo.org/show_bug.cgi?id=1129 (Tested with Video but forgotten the Audio part)
This could be a workaround for Bug 1129, but also not fixed:
https://bugs.maemo.org/show_bug.cgi?id=3091

https://bugs.maemo.org/show_bug.cgi?id=8107 (never used a normal Camera, on the Symbian Devices this works since ages)

https://bugs.maemo.org/show_bug.cgi?id=2557 (Send EMails only stored on the Device without the possibility to export them to the IMAP server)

https://bugs.maemo.org/show_bug.cgi?id=10366 (Trojaner at PR1.2 Firmware)

https://bugs.maemo.org/show_bug.cgi?id=430 (very old and annoing Bug, but still no fix or option)

https://bugs.maemo.org/show_bug.cgi?id=7358 (For this bug I guess they manage their Music only with the old Nokia Software for Symbian devices)

https://bugs.maemo.org/show_bug.cgi?id=6892 (Tasks are not well done at the Calendar)
https://bugs.maemo.org/show_bug.cgi?id=7125 (Notes also)

Good examples for the Phone and Adressbook part: (same target, different ways to fix it for the user, none are implemented)
https://bugs.maemo.org/show_bug.cgi?id=6083
https://bugs.maemo.org/show_bug.cgi?id=8655
https://bugs.maemo.org/show_bug.cgi?id=7195
https://bugs.maemo.org/show_bug.cgi?id=8297
https://bugs.maemo.org/show_bug.cgi?id=6444

The equalizer for audio output:
https://bugs.maemo.org/show_bug.cgi?id=1890 (harmattan as target for this? - I used it with my N95)


And don't forget the removement of features we have bought with the device:
https://bugs.maemo.org/show_bug.cgi?id=10318 (mark all Files in File manager)
https://bugs.maemo.org/show_bug.cgi?id=10332 (sort Mails by subject or size)


Edit:
Oh, and a other important thing:
https://bugs.maemo.org/show_bug.cgi?id=7512 (essentials and fundamentals in Database desing: NEVER EVER SORT BY ID! Use a ID only to IDENTIFY a Recordset, sort by something else, never by the ID and NEVER CHANGE A ID or create a scenario where a user or the software has to change the ID's in a table)