#3 The Miz
The Miz, believe it or not, used to be a bad talker. His early years in the company were shaky. None of that is evident today. The Miz is a master at not only controlling crowds but also in riling up his opponents and indeed, filling time, which is why the company is so keen on starting SmackDown with Miz TV.
The Miz's promos aren't repetitive either. Sometimes he can stir the pot. Sometimes he can cut deep into his opponent's psyches, such as when he told Daniel Bryan that he couldn't beat him because he couldn't abandon his moral compass and thus, abandon his supporters. Sometimes he can even make a promotion for his reality TV show entertaining enough.
The Miz is arguably the most complete performer in WWE, which is why he's so heavily featured. He always has something to do, which is more than can be said for a lot of people.