Those event equips helped me a lot back in the old days of me playing on regular servers. I remember getting a big boost in damage and training way faster with the event tube in the early days of maple.
In context of today, we sort of see this with the Frozen set, given to every burning character, however it's basically a gimped version of stuff like the Override set. Burning isn't just good for the free level ups, but also for the free gear that helps a lot in gearing up new characters.
This matters especially on reboot where you can't just buy all your gear. You don't realize how much time it takes for a solo player to get some starting armor that isn't god awful until you train someone up without burning these days, hence why so many players just opt to only make new characters during burning events.
I bet if stuff like yearly anniversary item sets came back, then people would be a lot more willing to get into the game as they'd be able to try many different classes in the span of a single event and build up their legion in the process instead of just the usual 2 burnings per event (2 tera and 3 normal for non-reboot).
I started reboot during the override event and I've got like 15 or so characters geared up with the override set, so it's clear as day to me that it helped a lot in getting started on a new server.
The best part about that set in particular was you could also use it very early on and it scaled up as you got stronger up to lv 100, where the whole set is a good deal better than frozen set.
"If you don't like it, don't do it" is and always has been a horrible mentality. Events are made to draw people back into the game and get people hyped to experience new content, not to make them come back to the game only to have them feel like playing the game is a chore.