I have a Samsung Note 4 that was suffering from battery issues. I purchased a kit containing 2 replacement batteries and an external charger over a year ago for just over $30 and my phone was back to 100%. Every now and then I get itchy to upgrade, but for my usage patterns there just isn't enough incentive to move. My biggest pain point will be sacrificing the ability to easily replace the battery and memory card.
Waterproofing not as important to me as the ability to have access to swap basic components.