You seem to be confusing two entirely different things here.
1. Orcs, the disorganised and not-terribly - threatening beings which have existed in D&D since the 1970s, and which have never, in terms of stats, or official setting lore been "terrifying". At most they might have been mildly scary to newbies who didn't know what they were.
2. Coroc's Orcs, which are apparently massively buffed in terms of in-game stats, have a totally different culture, one which is basically identical to Hobgoblins, and even possibly have a different appearance to modern D&D Orcs.
Claiming Orcs should be "terrifying again" on the basis of an unusual homebrew take on them is not reasonable. I could, with better justification say "Kobolds should be terrifying again!" because they were in a well-run Dragon Mountain campaign, even though that was basically the only time, because that was at least an official campaign. Heck I could say the same with Halflings because in Dark Sun, they are scary little cannibals.
It's also worth noting that the whole "make D&D scary and deadly" thing was absolutely done to death quite recently by the so-called Old-School Revolution games, like Dungeon Crawl Classics. Those games are cool, but it's clear there's limited appetite for that sort of thing.