For a jacket that I would use %80 of the time for climbing and winter backpacking:

-Take the design (fit and features) of an Arcteryx Gamma MX Hoody- add a few inches to the hem. Redesign the cuffs so they do not wear out in 2 years. Possibly add more fabric to elbow and lower arm/ yoke for durability. Get rid of the sleeve pocket and maybe one chest pocket.

-Use fabric similar to Patagonia's Ready Mix material, but actually make it stretch and make it durable. Keep the quick drying, wind resistance and light weight.

- Use Arcteryx colors (deep brown and burgundy)

Given this, essentical features are:

Above a harness hand pockets, at least one chest pocket, long arms, long hem, helmet compatible hood for people with big heads. Ultra breathable, but windproof, fast drying and tough.

Come in around 14 ounces, and under $250.