More formula options for TDEE estimate
Currently under the "Activity Level" tab, there is a list of set multipliers for estimating one's activity level as well as a Custom total kcal burned option. Having another option to use a custom multiplier as well (like inputting 0.3 for someone who knows their TDEE is somewhere between Sedentary and Lightly Active) would be a nice option.
Under the BMR tab, there is currently only options to use the Mifflin St. Jeor equation or inputting your own BMR directly. Having the option to use other equations like Katch McArdle (which uses BF%) or Harris Benedict, or perhaps the ability to add in your own formula with a list of variables would be useful to those who know the default formula isn't accurate for them (like myself) but don't want to custom add their BMR each time.
I'd be willing to pay for these features.