It has nothing to do with that. Todd Martin is a very complete all-court player, and his two-handed backhand is his best shot off the ground, same with Bjorkman.
Now consider this, if Bjorkman were just a little taller and had a little bigger serve and forehand (flunky, awkward technique that holds him back). He would have been a perennial top tenner for sure. In fact, he was top five at his absolute PEAK form. Bjorkman's very impressive in his peak form, he plays a swarming all-court game; but he can't keep it up for the duration. It's his forehand and less than powerful serve that have held him back. If those two shots were on for him on any given day, I would give him a good chance against anybody in the world. The two parts of his game that were always there for him, however, were his volleys and backhand--a FINE attacking two-hander. He could also defend and return brilliantly off that side as well, very versatile shot for him.
And what about Todd Martin? He also can defend or hit winners or approach the net or return seamlessly with his two-hander. What's held Todd Martin back is not his completeness as a player, but rather his lack of athleticism. He's a big, tall, lumbering looking guy...the problem is that he actually DOES lumber around the court. He was exceptionally slow for a top pro. Virtually every top pro who's made it as far as him has a great set of wheels on them or at least average wheels (like an Enqvist type). But Todd Martin was almost like in quick sand. THAT is what held him back, no bounce in his step...ANYTHING but his two-hander, which was by far his best shot.
What about Fabrice Santoro and Martina Hingis? They definitely play as all-court and then some as any. Their two-handers can slice 'em and dice and topspin and slash 'em and dip 'em as crazy as any body's backhand. In fact, Santoro can do everything Federer does with his one-handed backhand and more, a LOT more, he's a literal dice-a-matic...too bad he doesn't have any power to go with that. Give these two Federer's perfect tennis build/height for more power and they too would be more dominant...heck, Hingis WAS dominant.
Emile Loit's another fine example of just how varied the two-handed backhand can be. She has better squirliness and variety off that side than anyone in the women's game I feel. What she lacks is an imposing presence and size and power...or in the lack of that Justine Henin-Hardenne's absolute jock-i-ness (in other words, God-given athleticsm and explosiveness).
Speaking from experience, I can hit either one or two-handed backhands at a high level. You can attack with either, you can slice with either (did you see Mayer CARVE up the court like a surgeon against Agassi with his two-handed slice? Ever watch Santoro and Loit do the same?), you can BASH with either.
The thing is though, most two-handers simply decide to just BASH. It's not that the shot's not capable of variety, you just have to *choose* to use that variety. Most don't simply, because the two-hander makes it easier to just bash, it allows you to get mentally lazier in my opinion. It's like a crutch, doesn't require you to focus or prepare as intensely. And the thing is, just bashing the two-hander all day long is extremely effective, not to mention it simplifies the thought process. Knowing all this, it's no wonder most tour players fall into the HABIT of just bashing their two-hander. The one-hander it's harder to do that I feel. Why? Because often times if you're feeling off-balance or lazy with the one-hander you tend to roll your wrist for a loping kind of topspin (think Pioline on cruise control parked ten feet behind the baseline on one of his less-inspired days) or you'll just slice the ball, because it's less fatiguing mentally and physically then raring up for the bash shot a la Kuerten or Muster...now that's a lot of work. Knowing all this, I feel that the variety of shot one-handers employ is a habit born from those days when you're just feeling lazy.
