Im fine with this for several reasons:

1. The monthly price makes it where only those who really would use this will pay for it as opposed to a flat fee.
2. I think that this and Phantasia will be the only charged services (oh and a server transfer). This is perfectly normal for the history of FFOnline games. Remember muling in FFXI.
3. I have no space problems with my 2 retainers, so I dont care to get another one.

I will add that people on this forum love to attach to a certain point and ride it all the way to hell, so this will probably be the new "housing crisis" until 2.3.