Red-zone scoring is about team execution and creativity, that Rams and Jeff Fischer do not come to mind when I think of that. I can't put that all on Britt.
Also, he's not physical as his size indicates? I disagree look at the 0:26 mark, Darius Slay did as much as he could to execute the tackle, he got low, wrapped up and tried to force the receiver to the ground, unfortunately with the end-zone in front of him, Britt used his strength and dragged him to the end-zone. Any other receiver who doesn't poccess the size or physicality there would have been brought down.
https://www.youtube.com/watch?v=9k1F1JF7o_M
Look at his 2nd TD vs Detroit on the 2:37 mark, the guy took a CB, Linebacker and a dragged Kerry Hyder(DT) to the end-zone and completely bullied his way there. On the slant pattern, Britt already got the first down, if he was finesse like other receivers he would've went straight to the ground as soon as he made the catch, he didn't and broke those tackles thinking touchdown.
In Aiken's case, he got a stupid amount of targets when Steve Smith went down and while he preformed well, he did play with Joe for 10 games, who we know is far better than any Rams QB. Aiken later on played with not the best of guys behind center, but he didn't have much competition to take targets away from and once Steve Smith, Breshad Perriman and Mike Wallace arrived, he was back to the #4 role.
Also, it's not just the Rams way of doing things, the Falcons who nearly won the SB gave Mohammad Sanu a $7M per year deal coming off a 394 Yard and 0 TD season and can anyone in their right mind justify that?
In Pierre Garcon's case, he's not coming from a worse situation, I would legit say he's coming to a worse situation offensively speaking here considering that I'll have to admit that the Redskins offense is a good amount better than the Ravens. He's coming from a passing attack that ranked 2nd in the league and a QB who last year ranked among the top 5 and this year among the top 10. I don't know if you're getting a better Pierre Garcon here than in Washington. Kenny Britt is a different story and I'm certain you're getting someone who can play better than the 1,000 yards he put up in that horrendous offense.