I've been working with templates a lot recently. So far the experience in After Effects is not bad at all. Going in Premiere however is not so fun. I would suggest an expression control for timecode units so the user can decided what time they want the animation to appear. The other method of this is sliders and too many expressions to deal with like start time, duration, end time. The units are whole numbers and seconds so the user might have to do a bit of math or they won't be able to get to those crucial half seconds. (If anyone knows how to do this however please let me know, I have searched and can't find anything).

Furthermore on my experience:
The positions Axis isn't as intuitive as AE, meaning there's a delay (not my computer - I have a new iMac) so it's not as smooth as AE. Tried to find how to add only the X axis or only the Y axis but couldn't so that would be good also when adding position to Essential Graphics. The Essential Graphics window in AE is quite easy to read until you get too much information, this is where the dropdown comes in handy but moving to Premiere I can't process the information as easily - I have a processing disorder which also includes a few learning difficulties so improving this would make it more accessible. Maybe slight highlights or colours that separate the information.