Firstly: just saw that season 4/30 will start on April 5th. Yay!
Now, on to old canon. Having recently watched
The War Games, aka the end the Second Doctor Era, I was able to acquire
Spearhead from Space, which is the first adventure of the Third Doctor. It’s impossible to be exactly in the same position as viewers were back then, and not just because I already watched many Three episodes and know decades of the show were still to come, but it’s still obvious that it must have been a quite radical change for fans then, and a daring move on the part of the creative staff to play with the format in such a way.
( Colour! No more space travel (for now)! Employment! )