Well, first off I didn't dare to ignore meta tags. I started and was trained as a SEO specialist that website optimization is really important and part of it is optimizing and take advantage of using the meta tags. Working as a SEO for 5 years, I've never stopped optimizing a website and including the meta tags. I really do think and feel that it is important.
I've never tried it before, but then here comes this client who don't want me to touch anything on their website even just the meta tags. I told them and asked them, to just let me touch the meta tags at least, it won't affect the design or the look, it's just for the search engines, and they said "No!".
So I let them, I can't force them. I don't have an access to the website. So, I just do the link building and really tried my best to boost their ranking from NONE to something.
For 2 months, I've been convincing them to let me at least optimize the meta tags because there are no progress, not as much as what I am used to for months on working on a site - because usually there's a progress (at least a bit of ranking going up) in a month or two.
On the end of the 3rd month, I sent them the report and told them that it will be just like this if they won't let me optimize the website. Check out their rankings for the first 3 months.
I then resume my link building campaign, looked for the best quality sites and just few days later I checked their ranking again and take a look at the progress below.
Website owners, I do understand that it's a huge deal of giving an access to your website but really, website optimization is really important for your success - if that's what you really want, if you really want to rank and not waste your expenses in the SEO service that you've hired or your SEO efforts.
I hope this answers your question or concerns of having a well optimized website.