Everytime Blizzard introduces a new character you people shit all over them. Remember Krasus? Rhonin? Those guys were around before WoW even hit the stalls and you hipsters got all defensive over their power levels. More recently; Me'dan, Broll and indeed the new and improved Thrall. Don't criticise their writing then say you wished they'd do exactly what you hate them doing you lousy hypocrits
On topic, anyone who's read the new book will see that they actual make clear how humbled Thrall is compared to say the dragons. Sure there's a bit of a mary-sue moment towards the end where he substitutes for Deathwing but they make clear that any shaman could do what he did, Thralls only "over-poweredness" is his ability to empathise, negotiate, talk things through, comfort, support and inspire. He didn't rise to Leader of the Horde because he took the position with wicked awesome shaman skills, he took it because he was the best leader and inspired old virtues of honour amoungst his people. He is a good Shaman, one of the best but not THE best as that is not something you can measure, the measure of a shaman is his respect for the elements and his patience and understanding of them in the most pressing of times.
Stop hating just because the Alliance has a better leader in their child prince than their ruling king. Stop hating just because you have short attention spans and don't like to see one character developed upon, especially such a great character. Stop hating just because you wanna hate. Stop hating full stop or get out of my Lore