To you it has more value than a regular job but to me it definitely doesn't as being strictly side content.
Just like you said that people want CHM for the gameplay it can bring, that's the same reason many of us were asking for blu with the intention of having it as our main. The analogy you're trying to make would make sense for us if blu was a full job but wasn't the role that we would have liked. I personally want a DoM tank and was hoping blu would be that. Yes, I would have been disappointed if it was another role but at least I'd have the option to play it in the content I want to instead of having the choice made for me.
You asked for what I think blu would look like as a full job. I'd really like to see something similar to this https://www.reddit.com/r/ffxiv/comme...concept_pitch/
Or if it was a melee support like the "leak" was saying, then it could have a melee blu spell for each element (fire/ice/thunder/water/wind/earth) and you make combos with these. You're not able to use the same one twice in a row so that leaves 150 combos if we are sticking to 3 part combos still. There's your job gauge and how you fire off other blu spells. Or just finish balancing what's already there since it's so close already as Rei and others have stated.
The chance they adjust blu to being anything more than it is now is low and even more so that they change or open up the roles it can play beyond caster dps so I'd still wanting at least a melee/caster hybrid that is as close to 50/50 as possible if not an actual caster tank. Something similar to what enh shaman used to be on WoW or assassin/shadow tanks were on TOR. Right now I just don't really connect with any of the combat jobs and that's the biggest reason someone like me will unsub.