No.
I have seen De Zeeuw's analysis, and Stefan Buecker's article, and to a certain extent I used the info posted there.
But my statement that Black stands badly after 5.d4 is due to an in-depth analysis I have made after I had the luck to meet the Traxler in a correspondence game.
Right, I've found Frendzas-Kahl. Hmmmm. I'd thought 9...Rf8 was the best move (rather than 9...h6 etc) and then 13...Nb3+ (rather than Bücker's 13...Nc2+), but checking my old analysis with Houdini now, neither 14 Be3 Bxe3+ 15 Kxe3 Nxa1 16 Nd2 nor 14 Ke2 Nxa1 15 Nf3 is looking particular pleasant for Black. Hmmmm. 
4...Bc5?! 5.d4! makes you regret it.
A bold statement indeed
Are you relying on De Zeeuw's articles for that assessment? If so, I should say that he's wrong about quite a few lines there. But then they were from 2002 and engines are a lot stronger now.
No.
I have seen De Zeeuw's analysis, and Stefan Buecker's article, and to a certain extent I used the info posted there.
But my statement that Black stands badly after 5.d4 is due to an in-depth analysis I have made after I had the luck to meet the Traxler in a correspondence game.