Raid/Operation mechanics are always a touchy subject, no matter which MMORPG you are talking about. When developers change the way long standing fights work, people tend to speak up. In BioWare's case, an intended function of an encounter did not work as intended and when the team decided to fix it, a few raiders disagreed.
When Nightmare Mode was released, Overload had no activation time, but its ballistic component was not working (which meant Overload could be completely ignored). We corrected this in the patch. In Nightmare Mode, the optimal path will always appear on either the left or the right wall, so a wall will always be available for tanking the demolitions probes.
If you'd like to chime in on the matter, hit the official thread.