I've never had a problem with the covers coming off or battery getting dislodged on any of my phones, but like you - I don't think the sealed battery thing is that big of a deal really. At least until you have a bad battery which the odds are against. I don't think I'd ever use a smartphone long enough for a battery to reach 'end of life' that replacing it is a big deal. I suppose if battery life was a big issue on a device and there were larger / long lasting batteries available as an option - that might be a factor. Otherwise, no biggie.