Agreed, but style guides are factual enough for me. Anything that can be cited by a proper authority on the subject, or ideally more than one, seems to fall on the “factual” side of the line rather than “opinion.” At least in this particular case. 
(Let me 'splain. I’m both flexible and prescriptive in both my own writing and when editing fiction authors whose work will be read by normal people. But when I’m editing work for a corporate entity–in this case a bank–I know I’m gonna have to justify my rationale. That means I need cites, or at least a quotable rule I can use.)
Yep, that would definitely work, as would any number of rewordings.
I should’ve mentioned it from the start except that it seemed extraneous, and my OPs are usually epics so I thought for once I’d cut to the chase, but… with this project for this particular client (a bank), rewriting the Delicate Genius marketers’ words is verboten. Punctuation, spelling, typos are all fine for me to futz with. Rewording things, not so much.
(In fact, the sentence I gave y’all to examine isn’t actually the one in the brochure. No architects were actually enriched in the real thing. Had to stick to my NDA.)
Honestly, working for this type of client is extraordinarily frustrating. I vastly prefer writing that’s aimed at humans, to quote Quercus, but this is doc for the banking industry, so “human” doesn’t enter into it. 
If it weren’t for the absurdly high fees I get to charge them, I would gladly stick to my lovely, flexible novelist clients.
…But then again, the bank/corporate clients are what make my reasonable fiction author rates possible. So I mustn’t grumble.
Anyhoo the project is out of my hands, for now*, so thank you all very much for your input and help! I really appreciate it.
- I’m sure once another dozen VIPs higher up in the hierarchy get their hands on it and rewrite things, they’ll send it back for proofing a fourth time.
