Like HW release, we had to ditch our old relics entirely, for a new line, will 4.0 do the same thing? because it may make me lose motivation to continue working on my current one, only to have to ditch it after next expansion. as it's another 10 level increase, are we going to do the same thing again?

Thankfully they aren't a huge gill sink like ARR relics were (yet), but the time spent is still worth noting.