KingxOfxMisfits While it does make sense that she's useless out in the open, the same can kind of be said about the other Controller Legends, (besides Rampart, who has a bit more of a use with her barriers).
Although, the other controller legends can still get some use out of their abilities, so I personally think that the rebuilding doors perk should be moved to her base kit and replaced with a perk that lets her control how the ultimate wall is put up, (basically where you look around, is how the wall will go up, (as in, if you do an S movement, there would be an S wall going up)).
Furthermore, the wall would also have a setting like Rampart's ultimate, where you can toggle between a line wall and a freeform wall, (by default, (even with the perk activated), the wall should be a line wall so it doesn't disrupt gameplay or throw off players who were wanting to do a quick line wall to block enemies' line of sight while running away).
I personally think this idea would be a pretty good buff for Catalyst as she can be more defensive early on and it would allow her to better control open areas where there is no cover, (or she could also encase enemy teams with a circular wall, allowing for her team to push them from any side).