MRPG Lock Picking
Any player can attempt to pick a lock, this is not going to be a rogue-specific skill such as in most games. Lock picking will rely primarily on the tinker skill, though through the use of enchanted lock picks, potions, and other items, any player should be able to penetrate any lock. Players with high-tinker will be able to do it earlier and more easily/cheaply.
Lock Pick Check
Each lock is basically going to have a #-point assigned to it. In order to pick the lock, the player must meet or exceed that number. For the purposes of lock-picking, the term "item bonus" describes any item be it lockpick, equiped item, potion, or spell, that adds to their total lock-pick attempt check. The player's attempt at picking a lock is:
(Buffed Dexterity or Intelligence, whichever is higher, x Tinker Modifier) + (Tinker x Tinker Modifier + Tinker) + 1d20 per rank + item bonus
Example: a Rank 2 character has an Intelligence of 17 and a Tinker Skill of 10. Their Tinker Modifier is 2, so 17x2= 34. (10x2)+10=30. 34+30=64, they then roll a 6, so their total for the pick attempt is 70, the player succeeds if the lock is 70 or lower.
Note that a player without any points in Tinker will only have that base 17+1d20 to work with, and even on a natural 20 will be able to only open a 37-point lock. This is where the item-bonus comes in. For example a +5 lock pick throws on an extra 5 points. An item might grand bonuses, as well as a potion. So the player without a high Tinker could reach that 70 points needed to get it.
Locks will scale according to level and dungeon-difficulty. A dungeon intended for level 9 characters will have locks roughyl 10 points higher than a level 8 dungeon, since level 9 characters will have an extra 1-20 points.