Well. . . it is replacing my iPad Air, and my iPad's have already replaced my laptop. So, yes.
Not long after I got my iPad 1 (wi-fi + cellular), I realized it had replaced everything I normally did with a laptop when out and about. Actually, it did more, in the sense that I was far more likely to use the iPad 1 when I was mobile than I was to find a wi-fi hotspot, a place to sit down, pull out my laptop, wait for it to start up, and finally do whatever it was I had in mind to do.
The iPad was much more convenient for short interactions, was ideal for reading and looking things up, and was usable for email and some basic text entry. The laptop was better for the last two, but not better enough to make it worth the extra setup time and location limitations.
So, I sent my MacBook to my younger sister. I've only occasionally regretted not having a laptop, but not enough to bother going back to one. My most recent temptation back to the laptop was the introduction of the new generation MacBook. Not because I want what it could do, but because it was such a cool computer.
When it comes to cool and desirable, the new iPad Pro totally eclipses the new MacBook. Not just because it is newer (every tech lover's weakness), but because it fits my my life style much better.
But, I have to admit if it were not for the iPhone 6 plus I'd be a lot more cautious about getting an iPad Pro. Before the new iPhone I had a tendency to tote my iPad just about everywhere; just in case I wanted to read something, or had a few minutes to kill. With the larger phone I now leave the iPad at home unless I know I'll have some sit down time, and something I want to do that will be worth pulling out the iPad's bigger screen.
In other words, I've started treating the iPad a bit more like I used to treat my laptop. That makes the larger size and the probable addition of a keyboard case more acceptable. I get to keep my well loved iOS, instant on, GPS, and everywhere connectivity, but give up some of the portability and handiness of the smaller iPad in exchange for a more powerful device. One that now exceeds (rather than meets) most of my mobile computing needs.
Hold in mind I still have a 27" iMac (which I'm using right now). I'm not iOS only. I have a big screen and lots of storage space when I need them, and since it's OS X, almost everything important I do on the iPhone and iPad have second home at home.
Still, as my iMac ages (it is a 2009), I've started considering whether I need a desktop computer. There are only a few things I do on the iMac that can't be done on iOS, and the larger more capable iPad Pro has eaten into a few of those things. I can definitely see a day when my iMac dies or become unusable, and I decide not to replace it. The only real question is whether that will be this iMac, or the next one.
edit: Too lazy to fix typos and grammar today. Not that I ever catch them all.