I have been down that road, and have drawn some conclusions. There has been some discussion here and elsewhere about this very topic.

As Casey raised the question, the powerful access point is able to reach out further to distant devices, even use beam forming for much better transmission and reception.

Unfortunately, handheld devices will rarely have the kind of power to transmit back to a single access point trying to cover a huge property, to make the initial connection. If they could get connected, it would be fine, but without enough power to trigger a response from the access point, it is futile.

I was using Ubiquiti access points, and would place more than one on the property as needed. There was so much talk about Ruckus being the bomb, and guys said they just used one, even up to a 6000 square-foot property. I tried that in a couple of situations, and I am done with that experiment. It was unsuccessful, because an iPhone could not reach far enough to make that initial connection.

Alternatively, a decent access point with a high gain antenna that can mount externally, has more potential in my estimation. The antenna is the key.