Some basic idea to improve the dice system (D20) in a more immersive way!

Hi!
Fighting some people yesterday I used a basic d20 system (thanks to u/mapPrevious8411) and I want to try an upgrade of it to make it more realistic and immersive.

First of all me and u/mapPrevious8411 have added the crit! If someone role 15 or more (maybe we should reduce it to 18 or more) and on the other hand the other rol 5 or le (maybe we should reduce it to 3 or less) you score a Crit! It give you an extra free action after this one! (Kinda easy)

Second of all body size should count towards dice rolls, giving modifier like in dnd. It has to be balanced and not perfectly realistic to not make it unfair for the smaller one.

This would ad a lot of epic moment, when a smaller fighter beat a bigger one!

If you want to make it even more complex certain statistic could ad specific modifier to specific action!

For example, about the size, +1 if you are 20 lbs more weight then the opponent, +2 if you are 45 lbs or more and +3 if you are 75 lbs or more (to all the attack roll and defence roll)

Same go for the height: +1 if you are 0.3 taller, +2 if you are 0.7 taller and +3 if 1.2 taller. For balancing pourpouse we can apply this modifier but reversed for the "grappling" action (the smaller one has the advantage thanks to the low baricent)

Another bonus should apply when you have a martial art knowledge of some way and if you ever practice any of it for example.


Those are all idea I would like to test! If you have any suggestion and other ideas feel free to write e them in the comments! I will be out until 16/17 so I will reply later!