As a general Grom would be perfect, well assuming he would actually follow orders unlike his WC3 self at any rate. As Warchief obviously he's a disaster, despite the position's name the big boss needs to know about more than axes and how to bury them in people's skulls.
A criticism one could also levy at his kid to some extent. Garrosh was a lot smarter than daddy dearest but had the same crippling flaw of being an overly emotional prick. But a loyal Garrosh as second in command to a Thrall that hasn't had his IQ and competence bombarded from orbit would make a great leadership duo for the Horde. Alas, we needed to be taught the lessons of Pandaria twice, and instead dealt with Orc Hitler, then Wicked Witch Windrunner, and then had a council where the fucking elf starts Lok'tar Ogar-ing. Not the worst timeline because WoD's exists, but not that far either. Anyway I digress.
Not sure what Varok was doing back then, too. He didn't even exist in canon back when WC3, Rise of the Horde and Lord of the Clans were being written, so I'd assume he was lethargic like everyone else, and probably already too old to be Orgrim's likely successor.