Primary stability is a bit like bicycle training wheels - feels great at first, but it's worthwhile to take the time to do without them. Boat designers have a design trade-off between primary and other maneuvering options: tracking, turning, surfability, etc. If you pick a boat with high primary, the learning curve is very quick until you start to demand more from your boat, and then you hit a proverbial 'brick wall'. Boats like thew Nordkapp deliberately sacrifice primary stability for other seakeeping features, and they assume their paddlers will take the time to overcome lack of primary stability.
So I would suggest to take a BCU 2* class or somesuch to learn how to overcome balance issues. For me, it's hard to imagine an Explorer would give you problems in rough water (unless you;re over 6'4", 250 lbs), and with just a few hours of practicing bracing, you'll learn to take full advantage of the boat.