S1 has bumps here and there but it was never rubber monster of the week. In fact some of the best and most thought-provoking episodes were in the second half. The show was a little British and talky for the American viewers but Gerry wasn't under orders to re-tool or make drastic changes. It was selling well enough to warrant a second series which said a lot since ITC (American distribution) loved UFO at first too and green lit a second series with a bigger budget (which is the only reason why space 1999 exists) until the show got deeper and less action oriented, they reneged. S1999 despite its huge production cost coasted into a second series renewal comparatively speaking. FF didn't like scifi so he changed it into a bad lost in space.
Martin Landau hated what Freiberger did to the show. I remember seeing his first few episodes of series two and really felt it was far too different to the first! We had repeats of the first series on one channel here and the new shows on the other and the first series won every time! But Bringers of Wonder was a fantastic two parter and the beginning of the last bunch of shows!
JB