It would be quite easy for the devs to implement a way to do combat without tab-targeting enemies.
You might ask, why would we want this? 1. Because manual tab-targeting of enemies takes time, can get tedious, and may be immersion-breaking for some. And 2. Automated enemies targeting that occurs whenever you use a skill could also give the game a bit of the magic of real action combat games.
What would be needed is an option that will make the player automatically target and use the last skill used if that skill is:
a. Supposed to target an enemy
b. Used when no enemy target is currently selected
c. Used when there is an enemy within range of that skill
What we have right now is, if no enemy target is selected and a skill is used, the player is told that there isn’t a valid target selected and nothing else happens. By having the option I just described, players will no longer have to target enemies first before attacking, because attacking without prior targeting will result in targeting and then attacking, and we could thereby have an option that can be used to almost fully-supplant tab-targeting if the player wants to.
Please note, I am only suggesting this as an OPTION, not trying to replace the current tab-targeting system. And also note that it would actually give players an advantage over others using the existing system by no longer punishing players for accidentally using skills without having a valid target already-selected, and by allowing players to attack things with one less step (manual targeting is made automatic).
There could also be another option for use in conjunction with the above or separately: make automatic targeting only select enemies within a cone or straight-head area in the current screen and in front of the character, preferably allowing the player to customize cone/straight-line width. Currently, tab-targeting area is narrowed down to only what is visible on the current screen. What adding the option to narrow it further down to an area in front of the character would do is allow players to selectively target enemies by simply getting closer to them with the view of the screen by moving the camera, and then executing attacks (if used in conjunction with the auto targeting option).
Maybe as another option which should be at the sole discretion of the player since it would ultimately put the player at a disadvantage, this automatic targeting option could de-select the current enemy target (if any) and a new enemy target selected (or attempted to be selected) every single time a player uses a skill that targets enemies, which would make the game feel like some degree of aiming is required before executing attacks. Would probably not be worth it though, especially since this game doesn’t have an in-game mouse-look toggle option.