For me it suggested changing specific to specific. And key (as in encryption key) to decisive, vital, key, critical, fundamental or integral.

Then I realised it classified it as average when writing for accountants. So I flicked it over to writing for software engineers and the classification went to fairly effective (39% better than average) and the suggested changes remained the same.

I really like the idea, but the execution seems like it needs some work, at least for the examples I tried too.