Given how easy it is to accumulate Trophy Crystals, I don't think 10k is unreasonable, especially with how slow the devs are to make additions to PvP vendor items. I wholly don't expect another update to Trophy Crystal armor trade-in until essentially 2024; and that's me being generous after watching them with Wolf Marks all these years (1 armor set per expansion). The point is to keep retention beyond one, maybe two series, because apparently it takes them longer than that to add anything new.
5k crystals for an entire new portrait kit with all of the job's remaining abilities will likely just see the same problem we have now where we go multiple series with people lamenting on having nothing to spend trophy crystals on except in this scenario the devs have less potential options to use as future rewards. I'm willing to concede 5k per ability, but the object would be to create desirable vendor items that can't feasibly be bought-up after just 1 series and that should keep most people busy across at least 2 or more. People would still have choices to spend their crystals on, and would have to set priorities on what emotes and ability motions they'd like first. As much as people want to buy up everything asap, this is giving the devss some breathing room across several series seasons. Though that is me assuming they'd never go out of their way to do something like creating a 20,000 Trophy Crystal mount to help with the crystal-sink...
