I'm quite sure that you cannot make a very strong 50% <some element> deck, where <some element>'s cards are only peripheral, and don't affect the deck much.
In most cases you'd have around half of your quanta from that element (eg. when you take 10 pendulums and 5 other cards), so the deck needs to find a good use for that much quanta, or otherwise it would be ineffective. If half of your quanta usage is from <some element> then it is not a peripheral one, but it makes a huge difference. Even if the only cards you spend that quanta on are some generic dragons, shields, or something, it still affects the game as some dragons are easier to kill than others (or blocked by gravity shield), etc.
There are of course ways to make <some element>'s quanta less than 50%, for example taking devourers, or using 50% time for 6 precogs + 6 sundials + 3 pendulums for example, but these cards still affect the game quite a bit, and show the capabilities of that element (eg. capabilities of Time to make '18 card decks' and capabilities of Darkness to generate quanta with an offensive card). Thus these kinds of decks still have an in-element feeling.
So, generally I'm against any rule changes concerning Pendulums... and yes, that's partially because Time benefits quite a bit from Pendulums, but that's only one of the reasons ;]