Sedans and wagons can handle 2 kids on a roadtrip no problem, especially once you're past the stroller age (until then a sedan might have trouble but a decent wagon won't). The driving part and the fitting things in the car part, anyway. Wagon cargo space is so OP, they're comparable to their equivalent SUVs. The BMW 5 series Touring has 570 liters with all the seats up, the X5 has 650. Not too different honestly. The X5 also costs more, requires more fuel and is less engaging to drive due to its extra weight and worse aerodynamics (so probably nice enough floating at 90 km/h, but less awesome on curvy roads or high speeds like on the autobahn).

But I have a toddler that's not quite able to climb into the car seat and do up the belts yet and there have been many times I've wished for an SUV. Still driving my trusty old wagon, but... A nice SUV would be the same width x length and be nicer to my back and knees. There are actually pretty nice ones that are shorter than my old A6 Allroad. The Porsche Cayenne is technically smaller though I haven't noticed it being smaller inside. 300 kilos heavier (for the second gen; first gen is even worse since it has a proper 2 speed transfer case) and poorer visibility though, compared to my current car. So those are not things I'm a huge fan of.