We have two kids...a teen and a toddler...wide gap.
Once the youngest got old enought to fight with the teen we had to move the car seat out of the middle but there is still room to fit two kids and the seat without much problem. We have never had a problem with cargo space but my wife isn't the type to take the whole house with her when we travel. We have gone on several 4 day (long weekend) trips and a couple of week trips and have always managed to get everything back in the car, including shopping spoils, for the return trip.
I also have recently discovered that while you can leave the mini tail gate down and shut the top hatch, which is great for quick home depot trips, it is not a great idea to do this with 10 foot PVC pipes. It was like having 25 vents connected to the exhaust which start to snow when you hit 50MPH. What a mess..and the fumes make me high..well so it wasnt that bad
I hear what you are saying about the Pilot..I have driven them and honestly it is too much like a minivan. I say go for it. Unless you plan to have 3 or more kids than you don't need a minivan. And if you do decide to have a third, the next X5 may have 3 rows of seats!
Good Luck!