We began with xenForo, and as we built and added content Google started loving us. Most of our topics and content are weekly hot topics, they change every week, such is the nature of the manga/anime we are a fansite of. Recently, Google has been giving us a lot more love and on the days that the topic is at its peak interest, we are ranked first on search words that users use during that time period.
Out of the box, with no modifications for SEO whatsoever, from a forum that received 3000 unique visits per month, we now receive 45,000 to 50,000 visits per month. I'm just stating here, that the simple tools xenForo comes to you with that license price is much worth it, I've run a vBulletin forum before, and out of the box it didn't have the same results. IPB, I haven't tried, but xenForo I can vouch for. Google keeps changing the way it displays results and keeps changing its alithogram, Google itself advises breadcrumbs with HTML5 micro data. Google no longer pays attention to only page titles, but also content and anything related inside content to the search queries.
There's something always new in the world of SEO, I stopped paying too much attention towards SEO and just concentrated on making my members happy and building content unique to our site, and let xenForo handle the rest. I personally think many of the long time webmasters need to start bracing the change, it isn't the same as before and the Google Bots are also becoming smarter, 1000's of articles can have the same title but one stands above them all, why? Because Google bots have got smarter and "content is king" is the only thing that has been holding true in the SEO world since the beginning.
However, if the Title and SEO related to the title is your only concern, @
Chris Deeming has already provided methods and has shown how easy it is to customize and play around with xenForo. While something like this is important to you and you want it to be a toggable option, it has no importance to me (and I guess many of the other happy xenForo customers), so I believe that such a thing being in "core" wouldn't be required, while those requiring it can easily edit required templates to suit their needs.