Having completed a run thru series 5, i thought i would consider some general points.
Before series 5 was originally broadcast, way back in 1991, i had hoped that the eye-shield would have been dropped after S4 as an idea that didn't really work, but sadly there it still was....
In S5 with further sweeping changes, the last links to the original program had all-but gone. Treguard still remained, of course, but even his character seemed to have modified to an extent.
The biggest change was the introduction of a new arch-villain and sadly i felt that it didn't work at all. The earlier antagonists Mogdred, Morghanna (and even maybe Malice) had an arthurian-legend feel which seemed to fit in with the original concept so nicely. Lord Fear was more like a creation from a cheap pantomime. This is no criticism of the acting of Mark Knight, who gave it plenty of enthusiam, but i felt that the character was simply wrong from the start.
This seemed to be the general trend of S5. Between series 2,3 & 4 there had been changes to the cast and some great characters departed, but each time the producers created wonderful replacements. In S5 however, many of the new characters simply fell flat.
Sir Hugh didn't really seem to have much point.
Pixel quickly became samey and fortunately didn't appear later on in the series.
Aesandre was rather bland and didn't have anywhere near as much menace and impact as Malice, let alone Morghanna.
The most tedious of the new characters was Skarkill, a totally cardboard character.
Rayner Bourton did far better with his portrayal of the shifty Scaramonger. His improvised patter had some great lines, even more so considering he had to deal with several rather passive dungeoneers. Sly Hands got better as the series progressed.
For me the pick of the new characters was Elita, the stroppy cavern-elf who needed handling with tact. She combined the fiery character of Lady Velda with the abusiveness of Cedric and really gave dungeoneers some serious attitude, not all of which was undeserved. Stephanie Hesp really seemed to get into this character.
Thankfully there were some familiar faces. Motley was back in good form, Brother Mace returned in style and Hordriss was even more grand and pompous than ever.
The look of the series changed as well. Sadly the corridor of blades seldom appeared and seemed to be used simply to terminate teams who had fallen into losing status.
The causeways were a nice addition and really tested teams directional movement.
The spy-glass scenes in the "clue-rooms" (clue-areas?) seemed to provide clues easily and were less challenging than the traditional three-questions scenario.
The pace of the program, which had dropped-off in S4, seemed to get even slower. The eye-shield sequences were getting excessively long, to the point of being shameless padding. The dragon sequences looked great, but slowed down the game even further....
The array of teams was good tho. A couple of teams were very competent and some of the other teams were very entertaining.
In the '90s, i slowly lost interest in Knightmare from S5 onwards. At the time i assumed that i had simply outgrown the program (i was 17 when S5 arrived) but looking back it seems that from S5 there was a clear shift by the producers to aim the program at a younger audience. (Consider the introduction of Lord Fear in particular.) This could explain the fact that in middle-age i still really like S1-3 (and to a point S4) but find the later series disappointing.