Depends on your point of view and aims I guess.
From my perspective, no it's not a waste.
For reference, I am fully FTP, lvl 77, been playing for 4 years and currently have 71 5*'s in my roster (including all dupes & unlevelled crap etc). 26 alpha aethers in stock.
I don't have 6 war teams of 5* and by the end I'm probably using some of my best 3*s. 2LB is reserved for the best and those who I see myself using often and for a long time. Any hero who is going to be used but is not top-tier (relatively) gets 1LB. Any hero who might be used at some point or I'm levelling simply 'cos I've got no one better in that colour stays at 80 unless they prove themselves good in a fight!
1LB heroes are very useful for me, yes 2LB would be better but I can do without.
It also depends on the hero. Eg Von Rothbart, he's great, he can shut down a bunch of enemies and does good damage as well, however he's only at 85. 2LB will not improve him all that much beyond better survivabilty, it's his ability not his raw power that's his strength, so he's not top priority for aethers.
TL;DR? For me, no. For top players, probably yes.
Edit:
I counted up my heroes, out of interest.
Lvl 90: 14
Lvl 85: 12
Lvl 80: 16
Is this relevant? I have no idea