Not familiar with this . . .what's 30 second elevator pitch on why / how it's different than 5E, Pathfinder, etc?
In WHFRP 1st Ed. you created your character with one of scores of basic careers. For example, you could be a rat catcher. You may laugh but that was one of the best of them. For example, you had a 30% chance of starting with "a small but vicious dog".
The careers had exits to other careers. For example, soldier could lead to mercenary. But it could also lead to things like Captain or Scout. It sounds restrictive but it was utterly compelling and fun. The first thing anybody did when they'd created their Beggar or Boatman was start tracing a route to see how quickly they could get to an advanced career such as Assassin, Pit Fighter or Witch Hunter. And man did everybody want to get to one of those! Your career basically functioned as a smorgasboard of characteristic boosts and skills. You couldn't just expect to buy Navigation as a skill. What - you think you can just sit down one day and read a book on it? No, you had to learn the skills of the trade properly by actually becoming a seaman. Again, sounds unfun, but was actually awesome. And miserable. Good grief, a life of misery had never, ever been so much fun. You trudged your weary way through life always wondering if the next arrow would hit you in the eye and kill you. Hit locations were joyous in their effect. Everybody who ever played it remembers the one where you actually manage to sever someone's head in one go. The head flew 1d6 meters in a random direction and it told you to use a d12 to determine direction.
The only time I have EVER seen an equally perfect synergy between rules and setting is in Cubicle 7's Doctor Who: Adventures in Time and Space. In that one, the perfect blend of simplicity, open-endedness and initiative system that favoured talking and cleverness over hitting things matched the TV series impeccably. And in WHFRP 1st Ed. the gritty, low-powered, die of syphillis rules matched its setting just as seamlessly. Seriously - you might, somehow, survive the sword fight. But then you'd be killed on the operating table by a drunk chirugeon who botched amputating your lower leg.
Ignore Age of Sigmar. Warhammer is the setting that gave the world the phrase "grimdark". Seriously, this is where it actually comes from. It is one of the most miserable, hopeless, petty, backbiting, venal settings in the history of RPGs. Sure - there are apocalyptic settings, Lovecraftian mystery settings and all that. But they all feel almost adolescent in their "LOOK AT OUR DARKNESS". Somehow nothing ever quite matches the mood of trudging through a sewer in Altdorf during heavy rainfall when the water is flowing fast and carrying Sigman knows what around your knees as you try to earn a silver piece investigating a rumour that somebody's uncle's friend saw a giant rat down there.
Oh, and there are no giant rats. The arch lector's office has said so.
Seriously, WHFRP 1st is perhaps my favourite role-playing game ever. I really want to see what Cubicle 7 do with this. I really, really hope they manage to capture the feel and style of the original.