Yeah Brogni was very tough. But fortunately that was just collecting Epics. Karato was the worst cause for me cause it was the same level of Brogni...except you ALSO needed to get 4 each of 4 rares, and rank and ascend and fuse them for the Epics. I fused mine maybe an hour or two before I ran out of time!
Bonus Fragments + No Need to Farm 16 Rares gave people more freedom with this one, which was nice. Sure, that meant the DD2 was higher than normal, but I felt it was much easier to just run dungeons a bit longer than rank champs up that I was going to burn on the Pyre of Fusion. I like DD events cause I am at least actively farming for better gear while doing the fusion. Energy put into ranking up rares and epics you garbage bin to fuse the leggo is just energy gone with nothing to show.
As far as geared towards spenders, yeah, that's any live service game. Especially the F2P model. This one feels less so to me.
I got Champ Chase and Summon Rush both done without too much trouble. The key ofc is stocking up on Broadmaw Food and Relickeeper Food and saving your DT champs and previous fusions. When you start doing that, you know you can finish a Champ Chase without any real struggle, which means you can drop more shards onto the Summon Rush that comes before or after. I didn't event touch my DT frag champs again, as stocking up on the early game fusion champs in the reserve vault really makes a difference for the ability to finish fusions without needing to buy packs.
I have to thank one of our forum regulars from way back though, who taught me to be a religious shard saver and hoarder of fusion food, and honestly that was the biggest thing in making every fusion finishable. Previously, I was only doing every other or every third. Two plus years of pretty much every fusion though, worth the bit of time I spend collecting Arbalesters and such! hahaha