What makes a season of Doctor Who good or bad? Every episode is a variation of one of a few plots:
Aliens unleash some hidden plot on the Earth
Some human mad scientists experiment goes crazy
A remake of Alien with some creature running around killing the crew of an isolated spaceshipt
Something with Daleks
Every episode for the past three seasons has mostly taken place in and around England over the centuries. I seem to remember the original Doctor Who spending more time on completely alien planets dealing with shit that had nothing to do with Earth or England.
I really liked the the addition of The Face Of Bo. Spelling? The last episode ending added the crowning touch. I like all the seasons of Doctor Who, regardless of which episodes are my favorite. I hated Peri, but I still watched all the episodes with her. Even bad Doctor Who episodes are better than none or most other programing.