I completely agree with your take on the Celestion Blue vs. Celestion G12H30. And you are right, an EL84 amp cranked with a band sounds spectacular.A majority of these lack of low end complaints can be rectified by pairing the amp with the right speaker, shove a G12H30 on there and there'll be all the low end you need. A lot of people associate the sound of the alnico blue speaker as the 'EL84 sound' - but it's just the blue lacking low end.
I love El84s, they feel alive and rich. In the band mix they just.... work. Spooky magic.