It depends how you define meaningful to the plot and shock value. For example I killed off a major character during the climax of my WIP.
Did this death affect the plot in any way? Not really, since the story was pretty much over by then, although it did make for a more bittersweet ending. It did accomplish two things, however:
1) It made the villain more of a threat, and increased the tension during the final battle.
2) The battle ends with one of the main characters supposedly dying. He survives, and I feel this would have been more predictable if not for the other character's death.
Could either of these things have been taken out? Probably, but I wouldn't have been as happy with the end result.