Hitmarkers refers to the actual "X" on the screen when you hit a player. They are not necessary by any means, and not having them has just as many merits as having them, if not more. It's up for debate, but Islands of Nyne seems like it's trying to be competitive. That means there must be some skill based elements that players need to focus improving, such as recognizing when they hit a player (noticing subtle sound cues and blood spatter).
There's currently a vacuum in the "battle royale" games for a semi-competitive but still fast-paced shooter. Arma BRs are slow but incredibly tactical, often times a game ends by hearing 2 quick snaps and you're dead. On the other end of the spectrum, h1z1 (blegh) can have prolonged fights but nothing particularly tactical about how you go about fighting. Bounce around the map, pop a couple shots off to get people running to you, and get into fights. Fast-paced, but zero skill involved other than being able to point at your opponent (since there's RESETTING recoil as long as you pace your shots).
I think Islands of Nyne should try to hit that sweet spot in the middle, where you are encouraged to play tactically but can still have fun gun battles that aren't over in 2 shots every single time. Also it'd be nice to have usable melee weapons, like being able to sneak up behind someone and knife them for an instant-kill.