If Lori could jump as high as uppercut by default, then uppercut would be virtually redundant (apart from buttstomp blocks above and killing witches easily). Infact, that would make her able to jump as high as Spaz with enough momentum gained. However, you can jump higher than Spaz by default, if you kick certain enemies a certain distance and hold on jump. But that's very situational.

I'd like to change her special jump one day, which feels like the more sensible solution. It would grant height of some kind.

However, there's a thing part of the game called golden jump that allows you to jump as high as uppercut (it can be performed by all characters). Infact, it's marginally higher.

You can make it work by making sure the always run button is off, then standing and tapping shift roughly 7 times, and holding on jump the last shift (and don't let go of jump when you release shift!). It's not really the best solution since it pulls you to the left/right though.

You can pass all the official episodes with Lori without cheating. I've done it before many times.