Well the problem is that they bill it in that nature and they make lots of important deliberate connections to the old material which forces you to make that comparison even though it's not really appropriate.
I try to think of it as a sequel or successor to FLCL. Except without the memorable music. Except in those scenes where they borrow the Gunbuster score.
When I watched it earlier in the year, I couldn't help feeling like how much of a sequel it was given how it sort of fetishized the original in the same vein as the original did anime culture stuff.
I actually thought better of Gurren Lagann after the fact as it seemed more spiritual sequel to Gunbuster whereas Diebuster was a literal one .