Wordpress is the noob tool of choice, because just about anyone can make a default website with it. WordPress is not only the choice for noobs, but it is also server intensive, difficult to do SEO for, and almost impossible to get a high code to text ratio for SEO purposes. You simply cannot do SEO on a page if the contents of that page constantly change. Every time you throw a blog post on your "web site" you change the seo for the page. If they are disparate articles, your SEO goes to shit.
Wordpress is a blog maker, that's all it will do out of the box. It is designed to deliver the written word, perhaps a little media, in such a way that a moron could do it.
The problem is that a real website is not a blog, and dressing up WordPress with add ons does nothing to solve this problem.
WordPress is impossible when it comes to handling many pages, it only excels when handling blog posts, but that's it. Most wordpress sites look like and behave like a blog, they always will, and no matter what you do, unless you can hack the code, most visitors will immediately know it is an amateur site when they arrive.
This kills your credibility with your potential customer unless they are expecting a blog.
You cannot build what you want to in WordPress, you must accept the theme defaults. Even then, the theme will do all kinds of stupid crap, based on functions you cannot find. They have default behavior that will drive you insane trying to control. Even when you want an empty sidebar, WordPress will toss something there because the developer uses an "if empty" default that no one bothers to explain how to get rid of.
Almost no WP themes uses headings like they are supposed to use them, they use it for font size control. Many themes have no h1 tags, or multiple h1's and use the page title for the H tags anyway.
This is not to say that wordpress is ONLY a noob tool. If you take the time to learn PHP, and all the functions of a theme you can indeed make a real lookig website with wordpress, but most people cant even figure how to put an alt tag on an image, and getting the H1 heading small enough to look worth a damn is completely out of reach. Whet the hell, just use an H2tag, huh?
When you have to use the theme as is, your SEO is screwed, period. No plugin is going to fix that.
All you can say about WordPress is that it lets almost anyone build a website. They look like it crap for the most part.