I still think 24 was one of the best and most iconic series we have ever been treated to. It was also ambitious, and it really was sort of like a high-wire act, where the acrobat does something while his hands are tied behind his back. And the reason I say that is just setting something in that format handicaps you immediately and paints you into a lot of corners. It took them a couple of seasons just to figure out when to shoot so that the day and night scenes made sense.
So it wasn't perfect. Before you know it hot, blonde daughters are being chased by cougars just to fill 24 eps. My problem with the series was the tone; it put you on the edge of your seat for an entire 60 minutes straight, for 24 episodes in a row. There was little dynamic range there, few soft and light moments to offset the constant danger and suspense. The tone was also claustrophobic and paranoid, and almost racist, as every person with a brown complexion was the enemy.
So yes, at about 18 hours things started to have a certain sameness and a constant drone, sort of like when you look at a bright red wall for too long you eventually can't even see that its red because your whole universe has been red for so long that you have no frame of reference, nothing to compare it to. If 24 had separated the moments of suspense with calmer moments, or even moments of comic relief (which is the lesson learned in X Files and Breaking Bad) then the moments of suspense would have been all that more effective. Think Speed Metal music; loud and fast and hard is only loud and fast and hard (and entertaining) if it also has soft and slow to compare itself to.
But, and we can't forget, it was also brilliant, and the writers and producers (not to mention genius of suspense musical scorist Sean Callery) went on to wow us with Homeland, which proves they learned from those mistakes.
So, I am looking forward to the new 24, which has only 12 eps to fill and without the restrictions of the 24 "shot clock" that held down the original.