I honestly don't want to see Garrisnlul in FF-XIV.
We already have 2 followers that we can send on missions, they are called retainers.
Designing such systems takes A LOT of effort and DEV time, time that has to be diverted from other forms of content, as can be seen in WoD.
Instanced Housing will probably be done via the upcoming apartment system.
As for redesigns: yes there are quite a number of areas in FF that would benefit from an overhaul.
Class ability bloat would be one, horrible text menu interfaces (retainers/artifact chest) would be another.