I think most would agree that saying Brandon Jacobs "played well for a season or two and then teams figured out if you hit him hard, he folded like a cheap tent" is probably less than accurate. Borders on bizzaro world.
That's actually entirely accurate. Jacobs was a painfully mediocre RB. The only thing notable about that dude is that he ran his mouth far more than his play warranted.
He played much softer than his size would lead one to believe, and he was never able to shoulder the load as a full-time starter, which is odd for such a big guy. He had exactly two 1000+ yard seasons, which he managed to accrue thanks to the fact that he was sharing the backfield with Derrick Ward, who took enough carries to keep Jacobs from breaking in two. He scored a lot of TDs because, as a part time player, his job for most of his career was to punch the ball in in short-yardage situations.
I mean, if you are going to look at a relevant stat, don't compare career TDs of a nine-year pro with that of a three year pro. Look at something like, say, rushing yards per game.
Brandon Jacobs is 11th on the Giants (47.5 yards a game), behind such luminaries as Andre Brown and Rashad Jennings.
Morris? He's 1st on the Redskins (82.5 yards a game). Morris is ahead of guys named Clinton Portis, Terry Allen, George Rogers, Larry Brown, Stephen Davis ... John Riggins. (He's also ahead of anyone on the Giants. Hell, he'd be ahead of anyone on the Giants even if you didn't count his insanely productive rookie season. That team isn't known for its RBs.)
THAT is a tough guy. That's a guy who you know, when he takes the field, you can count on him to pound the ball all day and he WILL get you the tough yards.
Personally, my definition of a 'downhill runner' is a guy who gets tougher to tackle the further down the field he goes. A guy who thrives on momentum. Alfred Morris is definitely that.
Is he a complete back? Well, he's not much of a receiver out of the backfield. He's not particularly shifty. But he's a hits a hole smart and fast and he gets the yards that are there. Jacobs ran forward, got hit and went down. A lot. Sure he got ok at it for a few years as part of a committee, but noone ever worried about Jacobs as the focus of an offense, or even just the running game. Not ever. Morris has done it for three years, and he continues to be really good at it.