IMO they should lower the amount of stuff that is being put into game and put more stuff into cash shop instead.
If people would buy it, why not?

They could sell summon skins, relic skins, maybe optional paths in dungeons, you could buy other ways and choose which one you will run so you won't get bored so fast in expert, also additional housing plots, songs.

Many people seem to be also interested in PvP mounts, most probably A4s mount and EM primals mounts too?

70e for medium housing plot sounds reasonable I think.