I think the iPad is a great device. My wife uses her iPad everyday. Before recent retirement, I spent countless hours at work using MS Office on desktop and laptop computers. Also, working with in-house database systems etc. When I came home, the last thing I wanted to do is work on a computer...really. My employer bought my work computer (kind of a requirement these days for security reasons), so I just needed something simple for everyday life;
email & messaging
web
calendar & contacts
notes
simple documents and spreadsheets: Pages, Numbers, Keynote
PDF review/annotating: GoodReader
Photo
Video & iMovie
Finance: Banking Apps and Mint
Cloud storage
Games
etc.
For common personal computing needs, iOS is great precisely because it is so simple. I used to manage a team of financial analysts, so my work life was plenty complicated. At home, it is nice to take a break and have a more minimalist approach.
The iPad has come a long way from 1.0; Cloud storage, wireless updates, PC independence (don't need iTunes to setup), split screen, PP, Pencil, improved productivity apps (MS Office compatible), faster processors, more RAM, better speakers, keyboard connectivity, etc.. Can it go further? Sure.
As for me, things have flipped around a bit. I no longer have an employer purchased computer, but I am doing some business on my own...so I bought an MBA. I also bought the largest iPhone in hopes of getting some of the iPad experience without having to own three devices. It's a nice set-up, but I do miss my iPad.