my memory of the Sennheisers was of a mid-low centric phone
Would never have considered the ATH-WS99BT, because I'm really not a basshead -- I like extension and speed, but don't like the midbass bumps
I find your definition of the Senny more fitting to the AE than to the OE. So you probably have tried the AE.
It is a quite exaggerated definition anyway imo. mid-low centric is something else to me, like the Sony MDR-XB950BT or the House of Marley Liberate XLBT, and we are anyway still at a relatively high level (there are much worse kind of mid-low centric).
Anyway, tastes are tastes, so, the Senny is out for you.
You may have missed my review of the ATH if you consider it only good for bassheads. And you may have missed to read the sections "my ideology" and "my methodology" on the opening post of my Comparison thread, if you believe I would put at N°1 of my list something which can only please bassheads.
Yes it is true that I also test with EQ and that I may rate higher something which with EQ can assume more signatures (even if out of the box it is a bit bassy) than something that can only do what it does out of the box (i.e. neutral).
But, to get to N°1 of my list something must sound quite balanced out of the box.
Of course, it would be cool if you would use EQ, it would make your life much easier when looking for the right headphone. There will always be something too much or missing, out of the box.
But back to the suggestions, I believe that the ATH could please you but it is complicated for someone like you, and to be honest, I am not 100% sure they would be ok if you use them at very low volume. They have very big drivers, and big drivers need some volume to shine, otherwise all sounds a bit dull (which is where EQ would help, like once upon a time in the Amps at home there was the button "loudness" which boosted bass and highs and I never listened to my father when he said that that was only meant for low volume listening).
So, let's forget the ATH.
Ah yes, how can I have forgotten. The
AKG K845BT.
They may be what you want. They can sound "cold" at first, if you are used to the S1+, which, natural or not, they add some warmth to the sound. Which I liked. But I have also liked the better detail and almost no veil of the Akg. The highs are not so "airy" as the XTZ but are very good, some of the best around, without being harsh.
The bass is perfect for you, just right, not boosted at all. Not basshead on any means.
I still consider the XTZ superior (when used with Dirac), but, XTZ are on ear, so, it may be also a matter of preferences.
Other than that you find on my list only the Phiaton Chord which may be of your liking, really soft sounding, balanced, gentle.
Just now a guy on the other thread posted about the Beoplay H7 and you may want to read that and eventually ask him. You could ask thatonenoob about m&w m60 vs b&0 h7.