honestly, they're all great. what exactly do you have in mind when you say "ideal for learning"?
niseko is known for that JaPOW that will make those padded pants redundant.
ski-in/ski-out is available at the more premium resorts around the world.
convenience of transportation? that's the infrastructure of the country and you're spoilt for choice in most of the developed world.
cost? how much do you want to compromise? there's always china with a wide range of cheap options. or there's korea with its newly famous pyeongchang that still has a lot of cheap accommodation built from the old days when the area was totally unknown but they're all a shuttle bus ride away from the resorts.
just pick somewhere you're comfortable with, even chamonix.
also, if you are indeed looking into doing it a lot, you really should consider buying your own equipment cos having your own skis will aid in your learning process as you no longer have to adapt to new equipment during each season. on the other hand, renting will let you try a variety of equipment, albeit used and generally heavy/sturdy ones.
i don't know for sure about skis, but a decent first-hand set of snowboarding equipment for beginner to moderate levels can cost just S$800 in some countries, especially during sales, and around the world the rental for beginner equipment ranges between $20-70 a day, and skis don't differ very much from snowboards in terms of cost, so if you do your math, you can decide for yourself if that's better for you.
there's also the issue of logistics - most airlines will treat a snowboard/ski bag as one piece of luggage at 23/32kg regardless of actual weight; you just need to check the luggage rules before booking.