We believe that the understanding of first-person camera gameplay experience is still WIP. There are a lot of untapped areas that can be explored in this genre. But new ideas come with new challenges.
Melee combat can be very immersive in first person, but it puts the developer in a path of choosing between:

Flashy hack & slash gameplay
 or   
Deep & heavy gameplay

Hack & slash:
a great number of animation sequences and visual effects are needed to work out in hack & slash games. This type of gameplay is usually the choice for bigger studios with greater production budgets.
But this design choice comes with a risk; a repetitive button smashing type of game. Players have reportedly claimed about the lack of challenge in most these cases.

Deep & heavy gameplay:
a deep gameplay requires masterful design patterns in addition to that special challenge curve that creates what could be referred to as the game's magic.
Making an error in any of the design elements in this gameplay type could result failure of delivering that hook or rather magic spark and what comes next is obvious.

We have taken on the challenge of delivering a deep & heavy gameplay in Testament and hope to add a new approach to the genre.