Easily the most important duo of characters to ever hit the scene, They've both been family since they were united... I'm eternally grateful that Twilight Sparkle saved Spike from..... OOOOOOHHHHHHH NOOOOOOOOOOOO~ (G3)
I think they meant "tiny by the show's standards", and I tend to agree. Something looks just a bit off.
Other than that, though, it's nice to see something like this every once in a while. Let the show try to have it both (or more) ways at once, I prefer the sibling vibe between these two over all others.