Not sure what the issue is...I mean With event outfits its the same in any other game aswel. You get them if you participate in the event. If you miss out, then tough luck you will have to wait for the event to happen again.
All outfits, with exception of a few can be emailed across characters by using 6 outfit stamps which are cheap, plus you get 20 free each month if you are premium member. (Some are female/male specific so those depend on gender in addition).
Weapon skins would only be transferrable through support.
Any other outfits, you are dependant on the store rotation / rng/ trove, similar as in other games. While it might not be ideal or lackluster, it is what it is, it was something complained about since launch, and has not changed, so i doubt it will.