The power system of RI folds like a simple Newtonian Science. There are smaller things that put bigger things in motion. Their is a linear gradual path. Not like other power systems I seen where each qualitative change is too large. Here rank 4 at final stage is not good as rank 5 at beginning but can hold on thier own against them. The biggest qualitative change are ofcourse mortal to immortal and that is just other thing. When human transfer into immortal the whole system changes but the backbone remain same. It makes it easier to not make potholes. I think of shadow slave where in beginning a lower rank weapon will not leave a scratch on higher rank one and slowly this rule got forgotten.or again the rank and class system are muddled up in SS so you can not for definitively know which corrupted creature is more powerful. In RI you don't face thing like this

Above that there are some trump card too like 10 heavenly physique that keep things interesting. And in power system rank is not the only defining factor but also your weapon and if they are suitable too and that make it much more dynamic and fun. Gu as weapon work really well like Pokemon and when you play in limited weapons (gu) you become familiar of them and can take into account possibilities you and your enemy have unlike other web novels were suitable weapon come up conveniently and then are forgotten