I should also specify that it pretty much only happens when the unit is docked.  

I don't find it odd that local saved videos play ok. That makes absolute sense.

A video streamed from a website is far far more likely to encounter streaming issues.
You are relying on your internet connection, a web browser, flash player and the hosting site.
Whereas locally stored files rely on your HDD and the media player.

It is strange that you only encounter this while docked. Have you tested this with the same content while docked/un-docked?
Are you still connecting to the same internet connection while accessing a wired or wireless connection?
What site are you accessing? Is it You Tube - free provider, or Netflix or other subscription based site?

I see this as well, undocked when streaming. Running from an older desktop with Win 7, no issues. Running from another tablet (iPad) no issues. I am waiting for a replacement tablet, since 1/17 because the tablet came with non-functioning speakers.

I guess I should've been more clear.  I meant that since the locally saved files played so smoothly, it was unlikely to be a hardware/driver issue.  

My source was youtube.  For example, if I play the following video while docked, I get the constant choppyness but when playing off the dock its fine.

Docked, the connection is wired and off dock it is wireless.  Another reason I feel it isn't a streaming issue is because the buffer bar on youtube (the gray part) loads extremely fast and for a good portion of the total video length.  I'm beginning to think that the dock isn't up to standard and I hope that there are fixes in the works for it.

Do you have a monitor attached to the dock? (I presume so)

How is it connected? Are there any converters in the link for example - HDMI to DVI?

My choppiness happens when streaming from Amazon Prime Instant Video - full screen. The video stops, halts and gets choppy while the audio goes along fine. Same video from another desktop or TV on the same network runs fine. When I go from full screen to less than full screen it works fine.

Do you have a monitor attached to the dock? (I presume so) How is it connected? Are there any converters in the link for example - HDMI to DVI?

I do have a monitor connected via HDMI cable with no converters.  I've also noticed that if I change my project settings to just one device, the problem isn't as bad, but it still exists.

I'd love to hear from someone at Dell if this is a common issue with simple fix or if perhaps my unit is defective.

It does sound like an issue with the dock.
I'm out of ideas as to what else it could be.

I have a 7130 with the desktop dock, using a display port cable to my monitor and I watch You Tube videos in full screen 1080p everyday, no issues.

I can't imagine there would be a difference, but I wonder if Display Port technology has a higher bandwidth than HDMI and is possibly the culprit?  Does anyone know if there are different types of HDMI cables with varying bandwidths?  Maybe my cable just can't carry the data fast enough?

edit:  I just read that while there are different standards for HDMI (1.3, 1.4, 2.0), that they are device specific and that any HDMI cable should support any standard.  I wonder if it's my monitor.  Then again, this same monitor didn't have any problems with 1080p streaming from YouTube with my last PC.  And it also streams the local 1080p files just fine.  I'm baffled...

Like you say there are different standards for HDMI.
I dont know what the standard used on the dock is. Could it be that it is different to your monitor?

But then as you say, locally held files are OK at 1080p. This really is a weird one.