yeah I saw that bit too! he may or may not (probably not) be faster than he was 10 years ago but his endurance and cardio certainly won't be as good!
Unfortunatelly, i must agree with the second part of your post.
If i had to say anything negative about him is only that he is not in shape anymore. That surely affects his endurance and physical condition and even worse it sets a bad example.
Whether we like it or not, a martial arts teacher should be an example for his students and not only technicaly. Steven Seagal sensei has the technical skills, not doubt about it, but when it comes to nutrition and physical condition he does not reflect the discipline that a master should.
On the other hand, in order to be fair, his extra weight could be some kind of health problem (although that's no excuse) and let's keep in mind that other teachers fatter and less skillful as he is are rarely the target of such critisism as he has suffered.
He has been one of my greatest aikido inspirations and i'm glad that he is well and active!