This is one of the few truly sandbox MMOs that have been made since the early days of MMOs back before WoW made MMOs more accessible to the general player base. As such you can expect a lot more grind for each of the different aspects of the game, whether it be crafting, adventuring, questing or PvP.
The quests in the game don't feel terribly meaningful for the most part, but it is presumably by design so you aren't forced into having to do them if you don't want to.
The majority of negative reviews seem to be people who don't understand what the game is meant to be and were looking for something much easier to progress in.
For an objective review I give the game 5 stars wholeheartedly. The publishers have done a very good job of catering to each type of player as best as able. The graphics are amazing, with the top gear being very difficult/grindy to obtain there is great extended playability. Many gated materials mean having to gather in order to progress crafting so it doesn't become all AFK. Making gear to craft/gather with requires gold so it encourages you to experience other parts of the game as well rather than just buying everything off the market.
Great game worth playing, just be prepared for more of a time=reward approach than many other popular MMO titles.