The nature of wavium probably also cuts back on giant mecha. The more you give it to work with the lower the quirk level. Turning something like a retired navy destroyer into a spaceship? Heck, it's already got engines, internal air (water) tight hatches, radio equipment, etc. If you tried to make say an Evangelion by simply taking a large framework and covering it in canvas before applying the handwavium... Hello quirk city! Something that size will require a proportional amount of inner workings if you want to keep the quirk levels low.
So on one hand you can go through the trouble of building something the size of an giant robot, complete with equipment inside that already does something similar to what is wanted and is installed such that it at least looks like it ought to work... Or you work fast and cheap and end up with something that has quirk after quirk. "So you're telling me this can only be piloted by someone who believes they are Shinji, that the plug must be filled with a blood-wavium mix to take the place of the LCL, it has to have Cruel Angel's Thesis playing to start up and must have a constant non-repeating Eva soundtrack playing to continue operating, it really is dependent on an electrical umbilical and you do not want to know just how much power it wants, a cable which will snap at the slightest provocation no matter how much effort we put into reinforcing it, oh and the AT Field? The wave apparently picked up that AT stands for Absolute Terror and the Eva will only produce it in proportion to the terror the pilot is experiencing. Our first test pilot Shinji swore off anything to do with Evas after producing a field strong enough to stop small arms fire."
-----
Will the transhumanist future have catgirls? Does Japan still exist? Well, there is your answer.
So on one hand you can go through the trouble of building something the size of an giant robot, complete with equipment inside that already does something similar to what is wanted and is installed such that it at least looks like it ought to work... Or you work fast and cheap and end up with something that has quirk after quirk. "So you're telling me this can only be piloted by someone who believes they are Shinji, that the plug must be filled with a blood-wavium mix to take the place of the LCL, it has to have Cruel Angel's Thesis playing to start up and must have a constant non-repeating Eva soundtrack playing to continue operating, it really is dependent on an electrical umbilical and you do not want to know just how much power it wants, a cable which will snap at the slightest provocation no matter how much effort we put into reinforcing it, oh and the AT Field? The wave apparently picked up that AT stands for Absolute Terror and the Eva will only produce it in proportion to the terror the pilot is experiencing. Our first test pilot Shinji swore off anything to do with Evas after producing a field strong enough to stop small arms fire."
-----
Will the transhumanist future have catgirls? Does Japan still exist? Well, there is your answer.