I think that Korthia was incredibly hostile to alts – spending several weeks to get alt gear to 233 – but I think that Zereth Mortis is much more alt-friendly, e.g., buying 226 gear for any alt for a relatively small amount of anima (500 anima per account-wide 226 item).
And ZM’s mechanic for gearing up, which is a mixture of just doing WQ/dailies and progressing in Cipher of the First Ones, is both faster and more rewarding.
Korthia, however … that almost had me quitting. Fun content, but insultingly slow progression for altoholics.