They've had the ability to have multiple apps open at once, and to copy & paste between them for some time now.
The change to 'push home button to unlock' is relatively recent, and the switch to a lack of button had been done 5+ years ago on the Pre3. (might have been on the Pre2 as well, I only had the Pre & Pre3). And they finally get wireless charging, which was an upgrade for the Pre (released in 2009).
The UI became more WebOS-like, switching to cards that you can sort through rather than the strip of icons at the bottom of the screen. (although it's still one card per app, not one stack of cards per app, with related windows stacked together, even if it's the MS Word reader and the web browser stacked w/ mail, as that's how you opened those windows).
Now they just need to make the notifications less crappy. An alarm that you can shut off by grabbing for you phone while half asleep? Who's stupid idea was that? .... and I'm wishing I had held out for the blackberry. Finally made the cutover to iPhone this weekend, after trying to get used to it for a few months while the Pre3 was my main phone.