Regarding Shield Summons/Drums in general - this skill can be detrimental to players that want to keep away from monsters, like ranged characters usually, but most notably for sorcerers. More often than not it happens for this skill to be used by a pawn when standing right next to the arisen, attracting the unwanted aggro to the player's location as it is charging up spells. I understand this skill is part of your play style from what you wrote, and it is perfectly fine, but this is more of a heads-up about how your pawn might be perceived by other players.
regarding:
Actually i was running him with Strider earlier. Sadly needs more Bestiary so he actually can scather
Not sure what exactly you mean by that, but I can tell you right away that the only inclination that directly needs bestiary knowledge to actually work is Utilitarian. Scather inclination makes a pawn to prioritize the strongest foe from a group of monsters, when attacking.
About switching the pawn vocation: a pawn will get better at a particular vocation the longer it stays as that vocation. If you just switched the pawn to a new vocation, it will not be at it's best right away. It needs some time adjusting to the new role. Now, while you're lvling, you shouldn't be concerned about this, after all it is expected to switch vocations often. This is just something to keep in mind, when judging the pawn's performance.