Assuming that you're running a full SSR team, you have to remember that the difference is between 700% and 1000%. Furthermore, if you're running say 120% from Exceeds, then it's between 820% and 1000%. And then if you add Michael buff on top of that, it's between 920% and 1000%. It's still more damage, but you also have to remember that you lost 30% Elemental modifier from not running Shingen Lance. So unless you're running on-element with double P2W Eidolons, that is quite a lot of lost damage.
So, here is how burst works:
a) 500% base for SSR Hime, 550% for Awakened (significantly lower for SRs and especially Rs!!!).
b) Up to 500% from burst modifier, this includes everything like the damage portion of Exceed, PF and Hime buffs (like Michael buff).
c) Hime's unique personal effects. These are VERY RARE, and are usually something like 100% per token. Examples, Uriel and Pluto.
If you read old posts, you'll find that Uriel is considered a god of damage. This is because in the era of few Exceed weapons, she was able to increase her cap to 2m. Furthermore, she has very fast token generation, so she is able to reach 550%+1000% burst damage very quickly, and this is before PF damage increase. This allowed her to reach 2m damage very easily, something that other Hime simply couldn't do.
Nowadays, Uriel still hits 2m bursts very easily. However, that's "all" she does. Thanks to FLB Grids and other improvements, Hime with debuffs and/or team buffs can reach 2m bursts as well. This is related to your experience because, well, if you read old posts from days gone by, you probably get the impression that "OMG PF IS GODLIKE"
Which, you know, it isn't. Is it good today? Hell yes it is, just like Uriel is. But are they as godlike as they used to be? No, no they are not.
tl;dr; use offensive Soul weapons. The 30% Elemental is usually just too good to pass by.