I honestly don't think the issue lays with DayZRP, but rather DayZ itself. DayZ is a sandbox game, where the players create their own content through interactions with others. In the vanilla game this content is mostly trying to stay alive by avoiding or killing those whom are trying to kill you, and in DayZRP's case it's roleplaying. But besides all that, there's not much else to do.
The game itself is just too empty (in it's current state). The only thing you can really do is play dress-up with the various clothing items that are scattered around the map, avoid or kill zombies and talk with other people. The basebuilding is outright horrible (compared to other games), and serves no real purpose besides being able to store more clothes for playing dress-up. The survival mechanics are too simple, consisting of 'eat & drink to stay alive', with nothing else (besides some diseases) to spice it up.
Look at a game like 'Project Zomboid' for example, where each character has certain traits, weaknesses and skills that they can progressively enhance. Your character can get panicked when massively outnumbered, scared when an infected jumps into your line of sight, you can get stressed from certain events or even a nicotine addiction, and some other mechanics. All those things spice up the 'survival' aspect of the game, making it more then just 'Eat, drink & don't die'.
There's just not enough working content in the game to make it any more interesting then; Zombie apocolypse dress-up running around and maybe sometimes shooting people simulator.