Reading from the dev post and a little onward.

What I'm reading that I can agree with:
Receive a regional linkpearl that reflects only the current region (cannot participate if you are not in the region) (each camp, dungeon, and city could be considered a region)

Receive a new player linkpearl after completing initial mission.

Tools to quickly blacklist players and report for spam.

Tools to manage linkshells remotely.

Ability to quickly communicate between linkshells such as /L1 responding to linkshell 1, /L2 responding to linkshell 2, and so forth.

If companies take the place of linkshells, then linkshells would become player moderated chat channels of sorts. An invite only basis of

Not a fan of global chat. In my opinion, a global chat should only be used to desperately coordinate a trade, party formation, advertise a flavor of linkshell, or advertise a company.
/halfseriousmode on
Global chat costs 10,000+ gil per post.
That tiny lol message was better off sent in a /tell.
/halfserious mode off

The disadvantage of having regional chat and the like turned off is comparable to not joining a linkshell. You may miss things that could benefit you, and there are things that will not apply to you.