Honestly, I think I'd rather buy a booster box of this than Celestial Storm. I've become less interested in collecting due to the pull rates/how massive our English sets have become in the Sun & Moon era (in order to keep up with the billions of sets that are being pumped out of Japan). This is the most excited I've been for the TCG in... about a year, I think?
Set sizes killed collectability of English sets. Not just that they're too big to collect, but that they combine several smaller sets that did have their own themes/motifs, and turn them into a cacophonic mess. XY Evolutions is the only set I've tried to collect since the DP era, and that's because every card in the set did actually fit a singular theme.
A lot of other things have gone wrong with the series, from a collector's point of view – remember when secret rares were actually something to get excited about? – but I'd say size is the single biggest problem. The sets are too big.