I can't help but feel that ASW was initially scared about Liz being overpowered, even before the initial arcade release. She has an incredible set of tools, normals, and damage on paper. Most likely they were worried about how strong that could be, so they just made her laughably slow. The low health matters somewhat, but not as much as her speed does. If she was faster, her pressure could potentially be called mixup.
I feel that it's highly unlikely that, in the event of a patch or new release, Elizabeth wont get buffed. p4a was her test period and they'll figure out what they can improve next time. I think it's similar to how developers treat grapplers in first releases.