Well, I have just noticed that this thread started on October 30, 2014, almost seven years ago. People have been debating whether the iPad can replace a laptop for a lot of time now.
If, after seven years, the iPad still cannot replace a laptop, it is doubtful whether it will one day. Of course, the iPad can improve over the years to fully replace a laptop. But do not hold your breath. Do not buy an iPad now thinking it will be able to replace your MacBook Air/Pro (or whichever laptop you are currently using) in the near future. It will not. It will improve at a slow and steady pace, and your iPad will be long outdated before it is able to meet any expectations which are not already met.
It is frustrating for someone who wants to use the iPad for productivity to see the pace of software improvement. I have bought two iPads (in 2012 and 2016) hoping that one day I could be able to carry them with me instead of a laptop. However, I was never able to because the iPad cannot do all the office productivity stuff that I need.
If I ever buy an iPad again, it will be to use it merely as a tablet, for content consumption and without any hopes to see it turn into a laptop replacement. I will not wait forever to see it become something it was never meant to be.