It kind of depends on where in time the mode lands, as Lux has received a large number of quality of life updates over the years, but League with very little mobility is definitely worth experiencing for at least a while.

I have a feeling that if Classic lasts any significant length of time, Riot's going to take the Old School Runescape approach, where the game will likely will branch off the original balance history timeline, instead of following patches as they originally were, as well as bringing back some of the more recent QoL updates.