kennings, as this game is called in anglo-saxon, aren’t filler per se. Though they are also a memory aide (for the poet and the audience), they are primarily part of the way the skill of a scop (bard/epic poet) was judged was by how cleverly he could choose the right kenning for the mood and meter of where in the poem he was.

A saxon kenning for poet is “story-weaver”, and that’s actually very apt.

Wine-colored sea is a different story, I think. I've seen other languages also describe the sea as red, orange, etc. This is more of a situation with color naming: cultures separate colors on the spectrum into named categories in a more or less consistent way (e.g. blue and green come apart towards the end, and some languages still have the two merged). Red is one of the first colors to be named.

Apparently there is still scholarly debate around this topic: https://en.wikipedia.org/wiki/Linguistic_relativity_and_the_...

The "bard" usually also had an instrument, so it's highly likely that if he was having trouble composing/recalling the next few stanzas, he may have stalled for time by performing an interlude on his lute.