I might add something like "functional" as well. Which IMO would be a superset of "warm". I.e., a very functional sleeping bag will keep you warm enough at rated temperature. A very functional rain jacket won't have the zipper get wonky in short order or lose water resistance too quickly. A very functional stove will heat things for you with a minimum use of fuel and require little to know maintenance/cleaning/etc.

But certainly light, cheap, and durable are significant. In my own experience, "durable" is the least important of these. Few things really wear out for most backpackers with reasonable care, and those that do wear out are mostly "proportional" --- i.e., the wear isn't unexpected based on use.