Berdych's forehand changed during 2010 Wimbledon. Before, he was more loop and open in his racquet face during the wiper/pronation phase. Now, his wiper is far more closed and he comes more pronounced radially. He also gets his base planted more disciplined and patient as Fed does. He does not fall away backwards but his butt is far more over heels, with a lower center of gravity. Berdych's elbow is high but begins with the a more vertical racquet position, closer to Fed's forehand. I still would classify the takeback to be in the loop tradition, because of the high elbow. Berdych's elbow is about shoulder height whereas Fed's elbow is more rib cage level generally.
I would even venture to say Berdych's forehand technique is very close to what the 2005 Fed swing was, but with a more Del Potro like takeback, the abbreviated vertical racquet setup. Soderling is farther back beyond six o'clock (back fence) a majority of the time. He uses a pronounced loop to get there. Soderling's elbow is drawn back with the racquet face down.
Why I think Berdych's forehand is better is it is not as long as the Soderling radius and has a better chance at being more accurate. Being a few degrees off radially can make the difference in finding the correct line to the ball. Also, his takeback is more compact and precise, like a staff that is raised like a whip handle. Lastly, his stance does not have to be as wide and so Berdych does move around better than Soderling. Fed's recent hiring of Annacone does suggests he realizes his groundstrokes are being outgunned periodically by Davydenko, Del Potro last year, now Berdych and Soderling. And he has also to deal with Nadal, Murray and Djokovic. He must assert the middle of the court in another way, which is move up the middle and not be caught behind the baseline on the run towards the corners. Hopefully, he will also beef up his serve mphs and get the disguise back, not only his serve but his groundies as well.
His backhand needs better extension to the left of the ball, so starting with less of a bent arm and a more Western grip a la Kuerten might make it more solid. But I doubt he will make that change. If he returned to a more semiwestern forehand with a bigger loop and radius (his 2005 version forehand), he also would be able to cut more balls off on the run with greater extension to the right of the ball. I finally think he has to abandon some of the precision of the Eastern grip (smaller radius) in order to get some power out of his swing. Fed can make all these changes and be dominant again for a little longer, if he is willing. Hopefully, he will.