if it is really the case as being a "blocker" and a "gear check" why would you make the other bosses so much more insignificant and so much easier than him. also, wouldnt the actual lab keeper qualify as the gear checker before you even get to the bonus bosses and why are they not ascending in power, so if the first boss is at 1.4B then the second should be equal or higher in power.
... i mean i dont get why you are getting defensive on this unless you are a developer in disguise, but you are also pointing out that hard seems to be easier than normal which would be another indicator that ONE boss is out of order and got ways more power than he should have.

as for hard i think its equally to the normal except you have a few more mobs to fight, so if you can take it then go for it. on the other hand arent we all only doing the easy and normal level to get the plans on the shuffle? meaning that since there is no other plan than sirus (where we cant even farm mats for), it would be for the higher level chips only. so unless you have all 6-7 judgement spirits then i'd suggest move on to hard, however the ONE boss is still out of line that you can even beat while being in your banish form (at least i can) but its one of those things where you say "guess what thing doesnt belong".