The battery is normally the first part to go, so a battery replacement is the best way of making a 5 year old iPhone feel like a new iPhone. And really battery

The battery is normally the first part to go, so a battery replacement is the best way of making a 5 year old iPhone feel like a new iPhone. And really battery replacements is a bit too tricky with most phones, but I don't think standardization is the answer. Rather some acceptable treshold for repairability would be good. E.g. that you can buy replacement batteries for N years, that the phone accepts third party batteries, and that a pro or half-skilled person can replace the battery with some tools in 30 minutes without voiding the warranty even for a new phone. If those conditions apply then I'd much rather have that than a battery hatch or a standardized battery.