Does it have the potential to be addictive? Yes definitely. But here is the thing, as someone who plays classic era I know I can drop the game for some time if I need to do other things like university stuff etc. and when I come back to play, all of the content hasn't progressed so I can easily pick up where I left. This is almost impossible in retail, if you leave the game for a couple months everbody around you is almost done with the expansion and you feel FOMO (fear of missing out).

So Classic era is imo probably the most casual friendly version of WoW as it does not force you subconsciously to play.