Even if I think Lucas was trolling everyone with Jar Jar breaking the fourth wall and later igniting the long awaited clone wars, we can still assume that in the 10 years following TPM he became more competent; it just needs to remove his awkwardness all along in the process (like all fanedit do). But I also wish it was another character to replace him… a young Tarkin who later joins the military during the clone wars for example.
I believe that was the plan. He’d speak like a regular person because he’d have evolved/matured, but George thought that it’d be a bit too hard to take this huge change and leap forward. And we’d theoretically have had a lot more of him in AotC, but because of the negative TPM reaction, he was cut down.