The more I think on this the more I feel like both removable battery and removable SD storage are detractors from the device, rather than value adds. Obviously I recognize the utility, but I think of both of them as horrible bandaids for problems that shouldn't exist and could be solved much more elegantly. Both items solve problems that this device doesn't have (for most users) and would have an immense degradation to user experience.
Removable battery means:
1. The battery becomes smaller
2. The device design is compromized to accomodate access to the inside
3. People will buy cheap, knock-off batteries and have a worse experience for it
Removable SD storage means:
1. The battery becomes smaller (probably, not definite)
2. The device design is compromised to accommodate this access.
3. The device becomes less secure
4. Valuable development time is expended on this implementation and not on value add features or bug reduction
5. People will lose precious photos, etc to corrupted cards and have a worse experience for it
I definitely understand that there is a tiny population of users who really need these features - and those users should buy devices designed around those features. I have a hard time stomaching wanting a device that is designed with the purpose of eliminating complexities and then complaining that it doesn't have fringe features that provide no additional functunalites. That being said, obviously my position that these things actively make a device worse is even more to the margins in popular argument, but it is framed in the context of "most users", not users who base their device decisions on a single point such as this.
The selling points of the Moto X involve: having the best software, having one of the best hardware designs, having one of the best performing devices at a reasonable price point, not having much or any "waste", easily all day battery (and turbo charger for power users that spend more time on their phone than sleeping and working combined) and software decisions in favor of the user (such as breaking what previously would have been firmware updates into the apps themselves, allowing for more interoperability and a better software experience for most users).
Of course, they probably think me silly for thinking that having a physical button on the front is a deal breaker... so I'm okay with disagreement

I have no objections to increasing internal storage and/or improving battery tech to the point where one charge lasts for weeks... but making either thing removable is almost a deal breaker for me. It is not that I don't want other users to have the option - I just believe that option speaks to a totally different audience than those receptive to the X philosophy. My Shield Tablet has a microSD card slot and it remains empty because I've read about way too many horror stories of card corruption destroying a device's usability. Tolerating the presence of the slot is a small price to pay for what is hands down the best tablet available at any price point to date.
I'm not sure I can call the Moto X 2014 the best phone available on the market, but it's easily top 5, and while a few people that rank it thus might say that it is there despite missing these features, I firmly believe that it ranks up there because the design philsophy that makes it a great devices mandates that they leave those kinds of features out and include only things that make the experience better.