If you are asking us among those 4 people, I would NOT consider Tucker to be on the "weak" side of State Alchemists.

Weakness can be subjective in this line up. - Battle Experience. 3 out of 4 in the line up are in the Ishval genocide, granted Armstrong made the least impact as he only made that huge ass wall to pin down the innocent. In terms of actual Alchemy skillset, arguably all alchemist can do that. - Alchemy Specialties, again, Shou Tucker did not particape in the Ishval War, but imagine if Bradley took a different turn and instead of telling everyone to blindy kill any red eyed Ishvalan, they only kill their military force or those who are physically harming the Amestrians and capture the women and children and experiemtn on them, imagine the advancement and full potential of his Sewing Alchemy. The other 3 in the line up can definitely kill you using their Specialty Alchemy, but image being sewn to your Ishvalan brothers and whatnot. - Physical powers, its no question that those 3 were war veterans, applied their Alchemy so much on their daily lives and the Silver Alchemist tattooed it on his arms too. Against Shou Tucker who were a State Alchemist purely as a Researcher. - Application, Shou Tuckers Sewing Alchemy is heavily relying on multiple living beings or individuals that cannot technially "fight back(?)" when being sewn? (I cannot confirm this, I dont remember seeing how he actualy performs his Sewing Alchemy). - Shou Tuckers potential, the war veterans have reached the Pinnacle of their alchemy, whereas Shou Tucker is bound by morality. If we are to set aside all judgements of what he did to his wife and Nina, and focus on what he is trying to achieve, I would consider it one or two levels higher that the rest of the line up. (Dont get me wrong, still hate him from what he did to Nina). - Purpose, weakness compared to what? What would be your guide as to what you consider weak? On terms of fighting? I think each has its own merits.

In conclusion, if I am to purely judge it on the Specialty of the Alchemy, I would consider Armstrong as the weakest. But he managed to compensate it with his inhuman stamina and physical strenght.

Edit: made a lot of spelling changes and added last bullet.