That was one of the issues I had with the movies.
I thought those moments were cool, but the special effects weren't exactly up to the task. That being said, they were all practical, and I respect that.
That was one of the scenes that bothered a lot of viewers, though there were certainly worse ones.
Like elves at Helm's Deep. Just to let Arwen have some more screentime.
I can at least understand Jackson's though-process here. We don't see the battles in the North, so this is the only opportunity we have to see the Elves as a group taking part in the War of the Ring. Contrast that with Legolas' stunt with the Oliphaunt in the Battle of the Pelannor Fields.
But the Hobbit films are worse in this regard. We have even more outrageous Legolas stunts, the death-defying gags in Goblin-town, and other scenes I won't get into right now.