I'd go with...
1) Full priced game, normal sub and shop. <-- huge PR boost as everyone start to whine.. everyone expect B2P game. I wanna see them NOT playing this game, this is gonna be THE game of 2014.
2) Offer special discount for 1 year of 60 bucks only <-- PR boost, after all the wining... and I think they should be able to get enough people to the game for first year at least, Im sure IP and fantasy will hold. Devs get back their investement no brainer and dont need to add anykind of offensive shop in the future.
3) Drop game prices depending on how your population changes.
4) Add content 1-2 year and then drop off game price and sub, massive popoulation boost and relaunch for the game, all those players who've been on the edge about sub fee and all free players come to your game. Get money from a shop, I'd make more charity/donation shop tbh, you know your game is awesome after 1-2 year of lauch.
5) Piss off your competitors as your game is totally free and awesome.
6) Release ES6 to boost your population.
Regarding future content and design...
1) Id keep population on my mind 24/7.
2) Id add content to make the game more whole, new and old players play together. It should be absolutely perfect when you go free.
3) Good reward system for loyal players, for those who stick with you all this time, in-game and payment model.