> impressive corporate workflow systems
This is perfectly true - Symbian had a number of much-used discussion databases, the best of which amounted to a brain dump from some rather choice brains - when stuck at an airport there was no better reading than an offline replica of "Programming" or "Design". And each was tailored to need: some were purely for announcements without replies, some had threaded discussions, etc. It even got used for defect tracking, though the appalling search and execution delays suggested that this was better done by a dedicated system.
But that very flexibility demonstrated some of the weaknesses - it's all up the designer. Everything. So what features are exposed (and how) was quirky - some had separate buttons for "reply to post" and "reply to reply" (of course with lots of misplaced orphans hanging from the root), some had quirky ways of backing out ("NO! Don't press <Esc>, that's non-confirming irrevocable cancel entire posting!"), what shortcut keys are provided, it all depended on the database. So the "consistent look and feel" fell apart and even after years of use the muscle memory would misfire. In fact the only truly consistent bits were those most hated: CTRL-N always meant "create a new database" (not that plebs even have rights to do this) rather than "create a new document appropriate to my current context" (like an email), F5 means not "refresh view" (necessary since that wasn't automated) but "lock screen and make me enter my password again".
Of course this was a local failing: with better discipline consistent styles would have been developed and applied. But great designs find ways to guide the users into good decisions without removing their freedom and Notes seemingly didn't manage this. And even today in release 9 (2013) fundamentally poor UI persists, such as the lack of edit redo: it's great that finally multi-level undo exists (for text edits anyway, many more complex actions can't be undone) but undo too far and you can't redo: somehow in the move to an Eclipse framework IBM still managed to bring its custom, user-expectation-breaking, controls. As other commentators here have noted it wouldn't be surprising to learn that almost all their business is upgrades and license packs rather than greenfield site sales, which is sadly perverse of IBM: given the strengths of the core idea and the shallowness of many of the paper-cuts they could have been more than an industry joke.