You can use experience to increase your stats or train your skills so yes you can get stronger and better but there is no such thing as \"You gained a level and all your stats have increased a bit!\" in planeshift. You\'ll have to actively use your Progression Points with trainers to increase your skill or stats.
Some weapons have minimum requirements yes, like longswords or claymores for example will need more strenght to wield than short swords or falchions.
Monsters can drop tria, which you\'ll get automatically when you loot them yes. Aside from that they can also drop animal parts, food and weapons.