The division between T and P has been a constant thorn. Either make the jump up or dont. Its not that hard. I did it, a lot of other people do it, and not many people ever feel prepared.
You just figure it out. First prelim I did as a teen. It was the same as training for me back then. All the jumps looked the same in my brave youth.
I jumped back up the levels a few years ago after eventing nothing past training for a few years. Lots of young horses and sales horses, so they sold before the preliminary move up. I did my prep and the xc was the easiest part. I went slow, it was also the first event of the season, and got around with a foot perfect round and hit my distances.
You dont have to make time at prelim for the first couple times. Take the longer path to a combination or slow down farther out until you can jump it more out of stride. Eventually it becomes easy to just have a good ride.
I see jumps better at prelim than I did at training. I ride better at the level because I know that my room for error is much less, so I refrain from making foolish mistakes.
If people want it so badly, use black flag options on the T/P level we have now. This modified is just further dumbing down the levels. Either buck up and make the jump to the next level or dont. Its a simple thing really.