IE 4 and 5 were pretty good. ActiveDesktop was pretty cool. XMLHttpRequest turned out to be revolutionary.
It was only after triple whammy of Netscape being unable to further compete, the dotcom crash and the antitrust suit against Microsoft's integration between Windows and IE that IE got deprioritized by MS and slowly turned into the underfeatured mess every developer hated.
This take is pretty revisionist. IE4 wasn't good, ActiveDesktop and ActiveX were either useless or actually bad. AJAX was probably the only good thing out of IE, and I would not dare to call it an happy accident but I'm tempted
Although Netscape was even worse (if you resized the window, it reloaded the whole page), and IE for Mac at the time had the best CSS support out of any browser (it was a different renderer from IE Win). I did a lot of bouncing between browsers (Netscape/IE/iCab/Opera) back then until Mozilla came out and wiped everything else out.
It was only after triple whammy of Netscape being unable to further compete, the dotcom crash and the antitrust suit against Microsoft's integration between Windows and IE that IE got deprioritized by MS and slowly turned into the underfeatured mess every developer hated.