If the battery can be replaced easily without damaging the phone I'm in. The sooner other manufacturers wake up and do the same the more phones they'll sell.
The HMD Skyline should not only impress with a Nokia Lumia-style design, a 108 MP triple camera, a 50 MP selfie camera, and Qi2 support, but also with particularly easy repairs. A teardown by iFixit now shows whether the smartphone lives up to its bold marketing claims.