As a long time Pearl user (8100 then 8110), I was somewhat disappointed by the new keyboard layout.
I never liked the old one that much -- typing in French with SureType is a real pain, and I'm too lazy for multitap -- but going with less keys on a new phone seemed like a step in the wrong direction.
Still you got me thinking, and I believe you're right.
Like the other Pearls before, the 9105 is here for those who want their phone to look like a phone (or like a phone used to), and absolutely NOT like anything they could get some work done with.
What has changed though over the last few years, is that the Curves 8300/8900 and most notably the Bold 9700 managed to gain acceptance from those who rejected the 8800 because of its "bulkiness" and grim looks.
The Bold 9700 is a really good all-around smartphone (feature-full but still light and good-looking) and as such should draw the largest share of BB device sales by far, especially among current BB owners.
The 9105 however should be able to extend RIM's market reach, like the Pearl did on its time, just shifting the mark one step further.
I actually believe RIM would have got rid of the BlackBerry name for this one, were it not for the marketing headache what would ensue.