I feel the biggest problem this game faces is a lack of "worthwhile" and "realistic" challenges for the average player to overcome.

If you're an average player it is not "realistic" for that player to do end-game raids (I'm talking about savage content and what was previously binding coil of Bahamut). End-game raiding is simply not realistic for most because you need a dedicated group of eight and a substantial time commitment.

Currently the only "worthwhile" challenge for a player that is not raiding is Expert Knights of the Round. Void Ark, expert dungeons, roulettes are not "challenges" - they are initially fun events which quickly diminish into chores. Thus when the average player defeats Expert Knights of the Round - what incentive does that player have to further gear up? How can a game sustain itself by only presenting a single "worthwhile" challenge each patch for the vast majority of its audience to complete?

This is why I feel that the game needs expert / savage difficulty solo role specific challenges (solo instance battles and/or boss fights). Imagine if each patch released with three different solo challenges (one for DPS, one for healers and one for tanks). These challenges would be of a savage type difficulty initially and would progress towards an expert challenge if you reached the item level cap. The player could attempt these challenges anytime they wish without needing to find a party or worry about other party members getting frustrated and rage quitting.

The player would be able to learn the advanced concepts of the game and would be highly incentivised to play three different type of jobs and max each of them out (to experience all of the challenges). Think of it as learning to take down a difficult Dark Souls boss. Every time you earned a new piece of gear - you'll want to jump back into that solo challenge to see if you can take it down. The lesser skilled players would be able to catch up in later patches with the item level increase. The vast majority of players will have a challenge that they will spend weeks looking forward to completing (as opposed to new patch content that they complete in a day).

MMOs used to be about gearing up to overcome challenges. If the toughest challenges are only raid specific - a large chunk of the audience fully loses incentive to gear-up / play the game. There is already plenty of content for players who don't like challenges. What fun is new patch content if "all" of it can be completed without any thought or effort within a single day? It's time that the average player is given challenges that they need to work towards (gear-up and practice) to overcome.