Having done sulfonation with CSA and then converted the acid to the acid chloride with an excess of the same reagent, I think that you're absolutely right. The thionyl chloride was likely used for pedagogical purposes, but industrially it would definitely be avoided. One problem with this overall reaction is the formation of the ortho isomer when you sulfonate your product. From firsthand experience, the reaction of CSA with N-phenyl acetamide forms almost exclusively the para isomer at 10 degrees Celsius. One problem you will have is that your CSA will react with your free amine and you'll make the sulfonamide--but in reverse. The solution is to protect your amine; I did this with Ac2O.
So you're on the right track, but in order to fulfill the dual goal of getting better regioselectivity and preventing reaction of your aniline with your CSA (think of it as an acid chloride, it's best kept away from amines) you'll need to form some sort of amide first.
On a more industrial note, you could nitrate benzene, halogenate to yield m-chloro nitrobenzene, and then reduce to get to your starting material, which is how the compound is produced industrially.