It's definitely F2P now. I don't think any of the content is locked to free players. There's still a huge gap in terms of convenience between premium and F2P and about as large in term of progress: extra inventory space, better/more sidekicks, increased drops and experience. I assume the experience gap plays a bigger role at higher level, but honestly who here expect to keep playing a MMO long enough for that to matter?
It would probably also matter for PvP, but that's not really the main focus of the game anyway. And I think you need premium to run for governor and such, but who cares about that?
I haven't paid a single dime and feel like the progress is good enough that this isn't an issue for me. In fact, I feel like experience and drops might have been improved since the last time I played. I've had a bit more time to sink into this so I can say a bit more about the changes.
Dungeons are now available in easy and normal mode. Easy has the same enemies, but in fewer numbers, and the same drops. Most achievements require to be done in normal mode, but those aren't much harder to do with other people. Easy is mostly to allow people to solo dungeons with their sidekicks. The drop rate from dungeons seems to have been improved. Either that or the effect of prospecting has been improved. Either way, I managed to get a full set of royal gobball after only 2 easy run and most of the pieces for the imperial set. In addition to that, a new distribution machine thingy is available outside each dungeon. Running said dungeon gives you tokens (which do not take inventory space) which you can trade for whatever item is dropped in the dungeon. So you might still have to grind a dungeon to get the token, but at least you are guaranteed to get whatever item you are missing for a set.
There's also been some changes to crafting. Some recipes were removed or changed, generally to make them easier. Crafting is still grindy as any other MMO tho. There were also a few additions, but I don't quite remember enough what was available to comment on this.