It was a deliberate design choice to have red correspond to both Suns (orange) and Leaves (brown).
Fully half the cards allow 1-pip attacks. So red pyramids, which enable 1-pip attacks, are the most likely to let you do something. Having two different suits target those pyramids balances this by making them more vulnerable.
Also: Four of the colours give you different abilities (defense and the three different levels of attack). The fifth clour, green, is a kind of poisoned wildcard; you can use it to do anything at the cost of damaging yourself. So orange pyramids are just useless targets?
That said, you are welcome to play the game as you like. I'd rather people have fun with it than play it exactly as written, if it comes to that!
I didn't realize that; I must've misread the rules.
Having said that, I thought of something: Orange towers are used to perform Pawn or Court attacks only. What do you think?
It could work. It seems like it will make the game a bit looser (because some attacks could be activated using two different colours) and longer (because you are adding an extra tower per player).
There is no well to tell whether those are good results without playtesting. If you try it, let me know how it turns out!