How could someone be against removeable batteries? I can see where you say that it isn't a big deal, but to say that it is a negative is odd. I would love to have a removeable battery but not enough for me to roll with a V10 or G4 or 5. I carry a portable charger with me at all times. I hardly ever need it but it has saved me a few times.
Removable battery has some steep costs associated with it, including functionality, financial and opportunity costs. It's also solving a problem that no longer needs to be solved for the vast majority of users; and for those that would benefit from it, there are some equally compelling solutions.
The drawbacks of a removable battery begin with
design: Obviously the device has to be thicker and wider than it otherwise would be. And the battery itself must conform to a 'normal' shape, typically rectangular solid, whereas it could be shaped differently if it didn't have to be removable. The battery will be smaller than it would be if it didn't have to be removable, which impacts battery life and is a good lead into the next problem,
functionality: Battery life is worse with a smaller battery than with a larger battery, when all other things are equal. The location of the battery has to be different in order to be removable, which hurts the effectiveness of heat dispersion and reduces the availability of other components due to the lack of real estate in tight three dimensional spaces. This ultimately means less features are available without making the device bigger. The device is also physically less secure, more prone to breakage with user movable or removable parts. Next are
financial issues which I also tie to
opportunity cost: It costs a lot of money to have engineers moving everything around to try to accomplish a device with a removable battery without sacrificing too much of the rest of the engineering constraints. That money could have been spent on any number of more important things, such as better software, more product testing to proactively prevent recall level issues, faster software updates, better software testing, better performance on security updates, better advertising or those savings could even theoretically be passed on to the consumer directly.
Those are the cost considerations every OEM has to think about when choosing this feature over that feature, and on this specific feature this list is definitely not comprehensive but it's a good idea of the types of considerations. Within those is a market opportunity cost: will the sales lost from not having this feature or that feature be more or less than the sales lost in the future from having a poor experience or from having the wrong numbers on the spec sheet or from missing other sought after features? Fun job, right?
The way Samsung articulated it today (link I posted in this thread earlier) was pretty decent, they listed a couple considerations and then pointed out that in the S7 Edge they have a humongous battery, fast charging and even wireless charging. They also have data on who uses battery packs and many consumers are using battery packs. Samsung pointed out that with a battery pack or a battery, either way you're carrying something - and they feel that a internal battery that lasts all day and adding fast charging and wireless charging is a better solution for most consumers.
And this is all solving a problem that was "solved" over 3 years ago, when battery life stopped sucking in phones and external chargers and fast charging became more acceptable.
TLDR, there are definitely tradeoffs and each OEM has to decide which tradeoffs they're willing to accept and then each user has to decide which tradeoffs they're willing to accept and purchase accordingly. For me personally, a removable battery signifies the OEM isn't thinking things through they way I hope they ought to. For others, lacking a removable battery means that the OEM isn't even trying to sell the phone to them.