I think to my mind this is not so much a Symbian issue as a QA issue at Nokia, involving the S60 team and Symbian. Almost every major Nokia S60 launch has been dogged with serious bugs (7650, 6600, 6630, N80...) even if their launch was delayed (NM850iG, N91, ...). They have to get this right - if they can't then they will lose ground at the high-end to other platforms, such as Windows (still offering the full Windows desktop experience, ie. repeated crashes and OS reinstallations/updates every few months, but improving with every revision) and potentially the new Linux-based initiative when it finally brings a stable platform to market. While they're at it they could still usefully improve the UI as well, but that's another story.
In good news for Symbian though, the father of S60 is really rather happy that the N73 is just as great as he assumed, featuring adequate speed and an aluminium grille. No news yet on whether Orange et al agree.