For the "People won't buy gear since they can't resell it a few levels later" argument:

People already don't bother with updating their gear before 50, with the majority not spending money on melds even if they upgrade equipment regularly during their leveling, with some extreme cases where people will use the Lv25 GC set all the way to cap.

To make people actually invest money in equipment you have to make the game very difficult to progress in without regularly updating gear, either by making it a lot harder to defeat monsters, cast magic or even heal with weak gear, or by slowing down leveling up enough that buying that piece of equipment you're going to use just for 5 levels a worth while investment and not just a 3 hour purchase you're going to regret later that evening.

Also, this whole "Race to cap" mentality needs to go.