Brutes have Fury. At low levels, all the ATs deal similar damage, and have basically no enhancement. What you're experiencing is free bonus from Fury which is tuned towards rough balance above level 20. At very low levels (under level 15 or so) it significantly favors the Brute. Later on, your base damage falls behind a Scrapper's meaning the Fury stops being so much of a free bonus and more required to attain something like parity.
So it's just not that Scrappers take longer to mature. It's that everything starts out nearly the same and diverges later, but Brutes get Fury on top of that.
Blue
American Steele: 50 BS/Inv
Nightfall: 50 DDD
Sable Slayer: 50 DM/Rgn
Fortune's Shadow: 50 Dark/Psi
WinterStrike: 47 Ice/Dev
Quantum Well: 43 Inv/EM
Twilit Destiny: 43 MA/DA
Red
Shadowslip: 50 DDC
Final Rest: 50 MA/Rgn
Abyssal Frost: 50 Ice/Dark
Golden Ember: 50 SM/FA
Scrapers aren't so bad if you pick an origin that can use YINs damage enhancements (Natural or Mutation)
Ok. I made a fire/shield scrapper and just now a fire/shield brute. Playing the scrapper in the early levels cannot be described as anything but painful. I find myself running without my defensive toggle and still running out of end after two or three enemies worth of just fire sword and cremate.
My fire brute, on the other hand, is absolutely slaughtering everything in its path, and single blue drops every ten to fifteen mobs are enough to keep me above 80% endurance (plus with fury, by the time I've killed five or six mobs I'm one shotting even con minions or getting them down far enough with one hit that brawl finishes them off)
I haven't tried claws on a scrapper yet, but my claws/sr brute doesn't seem to suffer the end problems everyone's been talking about. I put some end reduction in my toggles and slotted my damage powers out at 25 mostly with acc/dam and like 30% end reduction from sets, and I can generally go most of a mission without having to stop for endurance, if I get lucky on spin and evis without even popping a blue. By comparison, every scrapper Ive tried I haven't gotten past 12 because of the constant endurance woes I've had with ever set. Only my katana/wp scrapper has been even marginally playable, but the relatively low damage is starting to get frustrating.
I'm at the point now where I'm just raising like four brutes so I have some to bring over to hero side when GR hits, I don't think I'll ever go back to scrappers, but seriously whats up with this? I wouldn't mind playing scrappers if they didn't seem like they were nerfed in every possible way.
Am I imagining things, or do scrappers just take longer to mature, or what?