Nothing about a 'good try' here. Again the subject is what would it take to get me to come back/pay for things. That would be one of them - I bought Khatai, I bought Turan. F2P is a nice idea but restricting access to what I bought is not - that's my opinion based on other F2P games, there's not much chance of changing that. Provided I enjoy myself enough I would look at buying the other boosters and subscribing. Again, it sure worked in EQ.
With Khitai they could restrict access to hard mode dungeons, allow regular ones to be run IF you bought the expansion. Sub or pay for access to hard mode after that. There are things they can do - right now it's too closed off for me to be interested in logging in.
With the base game they should strongly consider opening up T1 or T1 wings 1 and 2. Vissy should be opened up also.
As for WoW, don't know, ask them. Likely they don't need to go F2P with existing accounts YET. Maybe down the road who knows. I sure get a lot of "come back and try for X days" offers.
If AoC or any FC game had a fraction of Blizzard's numbers we may not be having this discussion at all... but good try.