Curt, While my choice of software (WordPerfect) has to do with the speed of editing a specification, more importantly, is an office master developed with narrow scope sections containing options that are easily identified, explained, and able to be edited with minimum keystrokes and mouse functions.
I can feel for and understand your dilemma. I have also taken over for a spec writer who retired and inherited many of their projects (and by projects, I mean mistakes).
Interesting that you predecessor “didn’t believe in Masterspec” but included manufacturer’s guide specs without modification. To me it sounds like they were on their way out and didn’t care anymore. Someone else would be along to clean up their mess.
You could do a lot of finger pointing and show evidence of the shortcomings of the previous specs, but in the end, someone is going to have to do the work to fix it. It might be now, as you rewrite the specs. It might be later during CA when they have to field a lot of RFIs and Change Orders. But someone will need to fix it.
Normally, once someone understands that, they see the benefit in paying to get it right, internally, now before it becomes a Change Order. Good luck.