WhereTo.Ski

The usual flow of booking a flight for me is - decide on region -> look for best resort in region -> find affordable accommodations -> find flights -> compare the different option -> book accommodations - > book flight -> book rental car.

Your solution doesn't align with the way I personally book a ski vacation, therefore it brings me little value..

Also, the your extra of snow forecast is nice but only relevant for last minute booking.

I guess your existing flow is more suitable for last minutes travel when you don't optimize for cost.. you spontaneously pick a place and book flight tickets.

that can be extremely costly since on there might not be available accommodation at a reasonable price and you'll have to overpay. a lot

On the other hand, if you don't optimize for cost there are plenty of agencies that can book you the entire trip as a package. so possible your target audience is very very small..