Also, some effect is lost in the translation as well.
Cicero's letters were meant to be read, I suggest you try them. They kind of feel monotonous at times, but it's hard to ignore how good a writer he was.
Oh I've read all of Cicero, I find him fascinating. He's the most online person I've come across in antiquity - the exact combination of haughtiness and crippling anxiety you see daily on Twitter. I find him equal parts contemptible and pitiable, similar to Pompey in some ways. But however effective some of his speeches were, a lot of the content was unhinged invective.
Obviously we're missing a lot of Demosthenes and Aeschines too - the former's physical gestures, the latter's actorly delivery. You can kind of feel the way Demosthenes hammers his point home, the monotony has a point. It's just surprising when you first come across it - this is the purported height of oratory, and instead of soaring, it's incredibly functional.
Also, some effect is lost in the translation as well.
Cicero's letters were meant to be read, I suggest you try them. They kind of feel monotonous at times, but it's hard to ignore how good a writer he was.