Not necessarily. Some poeple just lvl classes to 70 just to have it done (as you stated), or to see that classes job quest story line. There are jobs Ive no intention of actually playing but Ill lvl them just to see the story involved. Not everything is about using or playing a class at 70. Or in short, not everything is about the destination. Sometimes its about the journey.
I think the issue here is the assumption that old content is just old, and any new take on it is just "A new coat of paint". That may or may not be true in regards to BLU, as we dont actually know specifically how BLU will end up interacting with Old content. Furthermore, if nothing does change with old dungeons in of themselves, what is wrong with a "new coat of paint." This phrase is seen as a down side, but I think people dont actually consider the implications of a "new coat of paint". If you owned an old car but the engine was still perfectly fine, everything was great, but it looked beat up and old on the exterior, a "new coat of paint" can go a long way in livening up that car again. I do know the saying is about covering up old blemishes with new paint, but turned on its face, its also about restoring something thats older back to newer.
Why thats important is that BLU is supposed to do that. It's supposed to (from what we can gather) give you a new and unique way to interact with older content. This new experience with something older is actually (IMO) something the game needs. Now I think you just view it as "Well, Its just old stuff Ive been through. Been there, done that. Nothing's changed." but I think thats a narrow view of things thats robbing you of cool experiences all for the sake of keeping a narrow world view. Much like your view on lvling is that it is a means to an end, and not something that can be enjoyed.
Ill relate this to you, and maybe you can understand. People that can grind my gears a lot are people who power grind up to max lvl as fast as possible the second an xpac drops only to complain that theres nothing to do a week later and how stupid and boring the game is. It bother's me because it literally is a problem of their own making. If you play a game, but skip every cutscene, every chat dialogue, blow past every dungeon with no intent for gameplay but cheesing as much as possible, skip every little oddity and detail the game offers, all so you can get to max really quickly, thats on you for throwing away the bigger experience of actually leveling and seeing the world developers provide you. And I think this is a bigger problem a lot of people have. They think the important factor is getting to 'x' level. But MMOs (and RPGs in general) are about the journey there too. Point is, I think you may be to focused on the whole "getting to level cap" rather than giving due diligence and time to the journey there.
Well thats enough rambling.