Loved Asimov as a Teenager, in fact he was probably the first SF writer i really got into.
but after a while, i.e. reading the Later Foundation books, I begin to lose interest.
So while I do like his Ideas, his characterisation does look quiet chunky and 2D in hindsight.
However He did get me into SF and lead me to writers such Heinlein, E.E. Smith, Mccaffrey, etc. So While no one author has replaced him on my reading list, there are plenty more that I do like more.