Apologies, but I think your arguement is terrible.  Progress in Dragon and IG does not need to have any correlation with Spider or FK.  Just as progress in DT rotation 1 does not need to tie with #2 or #3.  
There are multiple ways to beat spider 20 and FK 20, especially now with the influx of new champs.  I would argue they are almost too easy now with all the new champs, and I struggled mightily in spider.  Though in retrospect, most of progression issues were gear related (solved only thru time or money + knowledge).  If you are stuck at normal 10, you are either 1) VERY new and DT should not even be a concern 2) Not even trying a reasonable strat, just hitting auto expecting 5 champs to win 3) Poor artifacts based on playing the game poorly
Same with this new boss, I cruised (50 was tough) to 90 hard after beating both prior rotations.  Why shouldn't this new boss require a different strategy or different champs or different gear?  It's not a gimmick, it's new content.  It's hard.  And in the past two days my clan has posted multiple videos of CCs beating it in very different ways.  
Lastly, I find the FW waves more gimmicky and annoying! 3 Valks no thank you, stupid paragon screwing up auto run in endless loop... no thank you