Well Federer back then, yes. Federer circa 2012 dumps that shot into the net more often and starts making all kinds of UEs with it. (See the Isner match) But yeah, back in his prime he could do some great things with a forehand. Nowadays though, it's fleeting. And he did lose to these two on hard courts so you could argue that Berdych and Del Potro's forehands (when they're on) tend to overpower Roger's. He's hitting it with too much spin nowadays so it tends to sit up short.
Gonzalez is retired but that was a terrific shot when he was in his prime. Terrific, aesthetically pleasing and really fun to watch. As for Nadal, it's a shot that works on some and it doesn't work so well on others. For guys who can handle the spin like Djokovic, it's not such a devastating shot. On the other hand, the Djoker lost to Delpo last year and he was match point down against Berdych in the WTF which is a lot closer than Nadal got.
If I had to choose a forehand (from any active player, right now) I'd pick either Berdych or Del Potro's. theKSHE if you don't agree, you're perfectly entitled to collapse in a fit of conniptions as your smileys suggest.
A lot of what you say has truth in it, but I think you perhaps overstate the problematic performances and don't account for why they may have occurred. Also, you don't mention the Berdych or Del Potro inconsistencies. Are there none?
Is Mr. Federer as consistent now as he approaches 31 as he was in his mid 20's? Probably not. Does he frame a few more? Yes. Does he hit more into the net as he attempts to hit winners on slow courts? Sure. But no matter. Just because he has descended from the stratosphere doesn't mean he has crashed to earth. I believe he still has more variety with excellence in the game on his forehand than anyone else at his level, and in conditions that favor him (granted, with so many slow conditions these days it's not as many), he can still beat the best, and make them look like they are in quicksand. His forehand volleys are as deft as ever, he just doesn't get the chance use it as much these days.
If you don't think he still has the great forehand with variety of shots, talk to any top players that he recently beat during his recent 2011-2012 24 match streak, Nadal, Tsonga, Berdych, Del Potro. Talk to Ivo Karlovic about the instinctive forehand lob that Federer conjured off Karlovic's dropshot about 1 meter from the net that he somehow managed to launch over the 6'10 (208cm) Karlovic's head at the 2012 Australian Open facing set point against him in the first set tiebreaker. Talk to #1 Novak Djokovic about how difficult it is, even in his prime, to survive the Federer forehand variety of shots and beat the elder Mr. Federer in important tournaments on any surface.
Does he have moments where his forehand appears to be off? Yes, especially when conditions don't suit him (slower and especially high bouncing surfaces). Isner and Fribourg? That court was laughable, with its high and irregular bounces and clearly didn't suit him. Of course that is going to produce more errors from Federer. Against Nadal in Australia, they played on the coolest, slowest conditions of the tournament. After 3 games with new balls, it was almost impossible to hit winners against Nadal. So he attempted quite risky flatter shots and hit a large number of forehands into the net in an attempt to produce winners. Was it the right strategy? That's a different question.
I'm sure one could point to other instances here and there where one could say Federer's forehand let him down, especially in the last 2-3 years as his collection of tournament has waned, but those moments are relatively far and few between. Many people tend to remember failures more than the successes, especially when a player has been great. His forehand is still an excellent weapon and one of the best in the game, even today.
Would one prefer Mr. Del Potro's or Mr. Berdych's forehand over Federer's? It's a matter of opinion. I happen to prefer excellence of a variety of shots over a one or two dimensional powerful shot, though again, any of these forehands are excellent and worthy of mention.