I initially was going to put Nintendo on blast for this one(supposed lack of external hard drive option), even though I'm not the type to complain a lot. But after much thought, weighting pros & cons, etc, perhaps there's a bigger picture to be seen.
I'm a bit disappointed(or was) at the lack of external HDD option right now, but I'm also well aware that the whole hard drive storage concept(which would be via the dock) could potentially conflict with the messaging and main attribute of the Switch - being able to immediately switch* playing styles and environments.
This will result in Nintendo taking that option of (affordable) external storage away, but it comes with the territory, and proposition of a device such as this. Our home consoles are quite powerful, but we can't lug then around everywhere we go. But we understand that this tradeoff comes with the territory. It's no surprise that we are seeing some things we may have to adjust to, with a system that's made with portability in mind.
I also can't be hypothetical about this matter. One the one hand, I hate how Nintendo screwed up the marketing & messaging with Wii U beyond repair, but yet I do kinda want a feature that would have the same effect on the Switch? What?!
"Sorry, you can't really just grab it and go like in the commercials, cause, umm...all your Hard drive data needs to be transferred...so,yeah".
I'm sure we'd be back here making thread after thread about how Nintendo screwed up again.
As long as devs don't get too crazy with DLC sizes on the Switch, this won't be a major problem. I'd imaging that developers would see portability of their game as a big selling point anyway. *For example*; Activision would have more incentive to ensure that CoD DLC on Switch isn't too bloated, potentially hampering the concept of playing on the go. Also, are we so certain that Switch developers actually want their game potentially limited to the home use only?
Finally the more I think about it; perhaps our perspective are a bit off. Rather than hoping for an external hard drive option that only complicate the serviceability of the Switch, we should rather hope that large capacity SD cards to see a significant drop in cost. That's the real perfect situation right there, if we're honest. If Switch does good business, and SD sales & competition see a spike, that could happen a lot sooner than we think.
Tldr; Nintendo Switch storage option, while expensive now, is quite forward-thinking. External HDD storage, while affordable, would contradict the Switch & play instantly message. Nintendo not repeating another console messaging failure here! SD card prices will drop even faster if Switch is successful.