They already have the job frames tied to PVP where you also get the PVP limit-break emote.

So I think they should add a second set of "frames", but this time it unlocks all the job's abilities for the portraits.

So first you buy the WAR frame for 1.5k, then you can buy the more expensive (say 5k) WAR ability pack and now you can used Holmgang, Shake it Off, Fell Cleave and so on for your portrait.

One extra pack of each job so you can choose for the jobs you want, and with a high'ish price tag so it's something you can dump trophies into.