The old episodes are very quaint. They are quite clearly produced on shoestring budgets, some of the plots are quite weak and i found it hilarious how bad the actors were at faking violence. But none of that mattered, because the team were clearly passionate and enjoyed what they were doing and did a good job so the end product is charming. Production standards have obviously moved on massively since the 1980's and we are better off. The modern episodes are much more highly polished and coherent but not necessarily more popular. Like someone else pointed out the massive influx of disney money did nothing and only exacerbated the train wreck which was the recent doctor who seasons.

Another film that had a huge impact was monty python and the holy grail which was produced with a budget of 75p and ends abruptly because the money ran out. But they just turned that into a running joke throughout the whole movie.