I'd argue that Season 15 didn't. It had a few good stories, but nothing on the same level as Genesis or Talons. It was at least half junk (Fendahl, and Invasion of Time were outright bad, and Sunmakers was annoying and pretty worthless, although it wasn't outright painful to sit through).
I enjoyed Image of the Fendahl, and The Sunmakers was also very good - that one was a "social commentary" story and got its point across quite nicely even to people who weren't familiar with the then-economic conditions in the UK.
Well, it definitely comes across (regardless of where you come from) as a writer who got annoyed by Tax Collectors and decided to shove it into a script. I'd say its the weakest Robert Holmes story I've seen, but it wasn't remarkably bad, just boring and irritating. Its like The Happiness Patrol. The story isn't hard to follow, but its probably more relevant if you're from the UK.