I didn’t read this suggestion as “pick a free platform”. Picking the one with the least path penalty is already implemented, and this should be always the same, unless penalties change.
And I think the discussion about dynamic platform allocation won’t be resolved for a long time. For me, it isn’t a priority. In fact I’m very happy that it is not dynamic, as this tends to be more realistic. Trains do use the same platform in reality, unless there are reasons like delays or works on the track.
I do understand that players coming from OpenTDD et al do like the different possibilities there. It is just a different design decision made by the developers.