There are not very many cool things you can get in this game that shows other people you are a good player. The only ones I can think of are the Emperor Costume and the Mount from Suspire Trifecta.
ALL MOTIFS in the game can be simply bought off of the crown store, and in fact the coolest items such as Monster weapon packs, crown mounts all come from there.
ZOS can at least add a few things that LOOK COOL for players to collect. I have a few ideas below
1. An exclusive monster weapon motif set that you can only buy after hitting alliance rank 50, and can only trans-mog to on that character
2. An exclusive raident apex mount that costs 5, 10, and 20 million Alliance Points respectively
3. A title for hitting 50,000 achievement points (No-lifer or Never-Goes-Outside) and a unique house
4. A mount for collecting every single motif on one character
5. New seasonal ranked arena game mode that is 3v3, and you get a unique mount after each season if you are in the top 15% of the bracket
6. Armor set for completing every single dungeon on Hardmode difficulty
7. Akatosh themed weapon set (with particle effects and all) for completing every single trial on hardmode difficulty
Anyway just a few ideas, feel free to add more