How is the fact that he's in federal prison for flagrant tax fraud being "constantly used as an excuse"? If anything, he's probably using it as an excuse for not being able to respond to the problems with his claims.
Ofcourse it was he had lots of valid points in his arguements
You mean like his totally bogus solar-mass-loss claim? Or like the leap-second "the earth's rotation is slowing down at an incredibly inflated rate" claim? Oh, yeah, you were going to contact the sites that repeat that claim in order to inform them that they're wrong. How's that project progressing?
One mind-boggling claim is his digital watch in a mine analogy, in which he's basically saying that the age of that mine is limited to the youngest feature in it (eg, a digital watch whose battery is still good), thus the age of Niagara Falls or the Mississippi river delta means that the earth itself can be no older than they are. So do you think that's a "valid point"?
About 10 years ago, Answers in Genesis printed an article listing bogus claims that creationists should not use. Hovind wrote an angry rebuttal to that article, because he still used most of those bogus claims, so they had to respond that those claims are indeed bogus and that he should not use them.
The man would regurgitate any and all claims he encountered. His presentations were PowerPoint Gish Gallops. He would repeatedly present himself to his audiences as an expert in science and math, when his actual knowledge in those fields are minimal. One of the greatest difficulties that his debate opponents have with him is that his understanding of science is so substandard that they can't have any kind of intelligent discussion with him.
No, his material wasn't good. And his being in prison now has nothing to do with it. His material is just not any good.