Anyway, the original remit of Dr Oho was to be semi-educational, hence the time-travelling to historical events.
Working genuine historical events into storylines is certainly nothing new in Doctor Who, though they mostly seem to be incidental rather than fundamental plot elements - eg the Doctor accidentally starting the Great Fire of London, and the Cybermen causing the 'meteor' strike that wipes out the dinosaurs (and Adric).
More recently we've had the 2012 Olympic torch relay intruding on a storyline, though I don't know if that really counts as 'historical'.
I enjoyed both the Rosa Parks and Indian partition episodes. They didn't feel like pointless history lessons to me, more like historical events providing background context for the human drama of the episode's main storyline in each case. And given that the target audience is kids, a bit of edumacationalism is perfectly acceptable in my book anyway.
In fact, I reckon the whole series has been really good so far - a considerable improvement on the last few series.
Bradley Walsh's agent is certainly earning his 10% at the moment - while Doctor Who was on BBC1 yesterday, he was also presenting The Chase over on ITV at the same time.