My main issue with him is how far off he can be on modern classics. 1.5 out of 4 for Blade Runner. 2 out of 4 for Taxi Driver. 2.5 out of 4 for The Outlaw Josey Wales. 1.5 out of 4 for Memento (really??) 2 out of 4 for The Shining. 1.5 out of 4 for The Thing. He originally also gave Alien 2 out of 4, and seems to have been pressured into raising that to a 3.5 out of 4. 2 out of 4 for Fight Club.Leonard Maltin is a pretty terrible movie critic, in my opinion.
He has a list of films he gave a 4 out of 4 that are very questionable, mainly a Gene Hackman western called Bite the Bullet that I saw on HBO some time ago and found to be nothing more than pretty good. 1958's questionable best picture winner Gigi, that odd and over-the-top Peter O'Toole moviemaking comedy The Stunt Man, Woody Allen's pretty funny but juvenile and undeveloped comedy Bananas, and that Cher comedy Moonstruck (I mean, it's funny, but it's a bad sign if my mom really likes it) all got this rating.
He occasionally, too, slaps movies that I didn't have much of an issue with alarmingly low ratings. What Dreams May Come, Fear and Loathing in Las Vegas, The Brood, Zombi, The Rules of Attraction, The Brood, Where the Buffalo Roam, Constantine, and Frank Zappa's documentary Baby Snakes all had components that I'd criticize, sure, but all got a 1 out of 4 from him.
I mainly admire Maltin because of the sheer scope of movies he's seen - he's seen everything back to the silents of 1914 - and have three versions of his yearly movie guide book. (One from 1994, which are his old-school reviews, one from 2013, which is the most extensive and best organized book he released - and updated many of those reviews, and one from 2015, his final release.) His reviews are very brief, and I like that kind of brevity in a critic.
I think I credit him for getting me into movies even if I don't take him nearly as seriously as I did as a teen.