Came across this post and read your review and other tidbits... your a passionate person and your always ready for a battle ;)
Anyway somethings i agree and some i dont, i believe you may be thinking in a certain way and maybe because your not getting what your believe is right then the product/plugin in rubbish.
It really does depend on the plugin and what it is set out to achieve, i dont user squirrly for the record but just seeing its feature videos it seems to be more of a content marketing tool rather than a hardcore seo tool.
I have also used many seo tools over the years, some are rubbish some are decent, but they all have features that i believe any seo needs, not because were lazy, far from that son, its because you want to be more efficient. Some of the tools are not even meant for the hardcore seo and more so for the basic beginner which i believe squirrly is targeted to. Some people dont know the ranking factors and need help in this respect which i believe many plugins achieve.
For example i saw you smashed the yoast plugin, i use the yoast plugin, why ? not because im lazy but because i can add meta's and features to the website much much quicker than doing it manually, for example, the xml sitemap feature, the authorship feature (although defunct now, it was useful), publisher meta (still relevant), twitter, facebook meta's, a visual guide to the rich snippet for the title and description meta and to know when it cuts off. Do you honestly think im going to sit there and count the amount of letters before i know its going to get cut off ??? no way, id rather visually see it within seconds rather than minutes.
The yoast plugin also modifies the header file if necessary if it finds seo problems with the title tag, ive come across some themes that have issues with coding and the yoast plugin has detected and fixed them. So the comment you gave on that no plugin actually fixes anything seo related is incorrect.
On page seo ranking factors are important and yoast does give some insight into this, but its not complete, i have found EasyWPSEO pretty good for onsite factors more than any other plugin ive used to date.
Your comment on keyword density is incorrect as well, there are some plugins that do infact count keyword density by reading the entire DOCUMENT not just the post or page content. EasyWPSEO is one such plugin that actually reads the entire document and gives a good indication of density levels, and density is important its part of over optimization, if your keyword density for a keyword is 20% and looks spammy then yes you may be penalized.
Your right in saying however there is no plugin that modifies h1, h2, h3, but logically that is not possible as that is up to the content creator to create those headings appropriately.
The big question is which i see your seeing red about is the EMD match to the titles tags that squirrly offers advice on.
Im in the middle here, i do not think that its completely going to devalue or not rank you just for that purpose, i also have many EMD domains ranking number 1. BUT and its a big BUT, as you would know with the rollout of future algo updates to penguin or panda this MAY be more of a problem down the road. As you would know heaps and heaps of site got smashed in the recent penguin update, one factor is the over optimized anchor texts, its all about ratio now and how natural it looks. I have had to re-evaluate the sitewide links we created to all our clients websites we built over the years and update the copyright information with our exact match keyword to our website due to the ratio being completely out of whack... something so small back then is a big deal now.
The biggest thing to take away from all this is does the content, backlinking, anchortexts, whatever strategy you want to use... IS IT NATURAL looking if something looks over optimized or looks like your trying to outsmart google then yes you could be setting up for failure so in concluding what squirrly is saying re the title being exact match to the domain is a valid point, but not the only factor by far.
Ill be taking a look at squirry at some stage and install it and see what benefits its gives at some stage but im too busy at the moment :)