Hopefully, they will stick to their present systems, which have served them well. I flew on them a few weeks ago for the first time, although I was skeptical I found the unassigned seats a welcome change. If you want a good seat, check-in online when check-in opens 24hrs ahead, then if you are super picky make sure you are at the front of the first line boarding. The gate announcements especially are so refreshing. About 4 or 5 instead of the usually 10-15, most of which are preboarding anyway.
If they start going international, like the article says, then they open a new can of worms. Anything involving Customs and Immigration immediately brings unimaginable problems, fines and extra charges.
Like my old boss always said (Western then eventually Delta), "The reason they are so successful is because they keep it simple".
The only thing a customer should expect for his/her loyalty is good service