Haven't you guys notice that Studded body has the same stat bonus with the leather body armor dropped by the barbarians ? Even monk's robes that are sold in Rimmington have better stat bonus than studden body [ 8 prayer bonus i think ] . here's my suggestions [pick either one] :

1)Increase the studden body stat bonus .
or
2)Decrease the other lower armor bonus [monk's robe,leather armor] .
or
3)Increase the price of monk's robe sold in Rimmington .
or
4)Trimmed [t] and Gold [g] studded armor gives more bonus than the normal one .

Trimmed and gold studied bodies don't do anything really it's just cosmetic addition (to make it look more beauty)

I'm with increasing the state of it considering your statement that it has the same state as leather one.

If the stats are really the same, I prefer to go with increasing studded body stats.

I feel there's a whole lot of lower level armour that needs to be fixed up.
For example, iron boots dont have any bonus whatsoever.

Agree with increasing the def on it a bit.
I don't think increasing monk robes would have any sort of impact.