I'd say gamplay comes before codex-lore-autism.
Omiblades are fun, kay?
If you really think about ME-physics, there is nothing that provides protection against high energy radiation. That would IRL not only render insterstellar travel an impossibility but also make something like an X-ray laser the ultimate weapon. And yet we see only projectile weapons in game
Obviously, gameplay comes before lore, but this is one case where the two aren't in direct competition. The action of stabbing someone with a deployable blade is super fun regardless of what the stabbing apparatus actually is, so why not have it make more sense?
However, omni-blades aren't the highest priority on my list of things that need to be fixed. I'm more concerned with stuff like omni-bows, which seem wholly unnecessary in a universe that uses high-powered sniper rifles. Again, the issue isn't the gameplay, rather it's the fact that the omni-bow could be so easily be a "wrist-mounted kinetic launcher," instead of a replica of outdated medieval weaponry. As of now, I'm perfectly content if only MP takes such liberties with lore and setting so it can have fun and visually distinct classes, but BioWare should tread more carefully when handling the main game. When BioWare bends the lore needlessly or otherwise, the credibility of the universe suffers, so for the sake of both fun and believability, they should only change things if it makes the game demonstrably better.