Since we don't know what is coming out in an arranger kb
at this point there is no reason to make a best list because we definitely don't know what is coming out yet.
Just like the OP suggests "Now we Wait"
I am doing this too long to not think something will
come out down the road. Not saying I will buy it or like
what it is but it is surly coming. Then at that time I will have contemplated my needs again and determine what is the way to go.
With only 30+ years hopefully left on this planet if I\m lucky
I want to make myself happy musically
as this is my passion and has always been my whole life.

Is that you Yogi Berra?

No lists include "future maybe entries" They can't ... we make our choices based on WHAT IS. Right?
... and what's with the third person ref to the OP? Are you reading Bob Dole's book?

Best brands based on what exists today:

Tie: Korg/Roland
Ketron
Yamaha

"Best lists" need back up ...
and that being I have to HEAR what people are talking about
there lies the real best IMO always.

You've heard all of these keyboards-heck you've owned them all.

Exactly I know what they can sound like ....
I was referring to hearing or describing
why your choices of "best" was created.

Korg-2 game changing features. Songbook feature is the best "registration" system IMO hands down. Also, the TC Helicon harmony and vocal section is the best. These two features give it the edge for what I use an arranger for (singing and playing country songs at home).

Roland-Easiest operating system and good sounds. If they had a touch screen and harmony they could overtake Korg. Ease of use is important to me as I want to play and not flip through manuals.

Ketron-I have never owned Ketron so take it with a grain of salt. But they have the best drum sounds and that is a huge plus. The 2 most important sounds to me are drums and piano. I have read their manuals and I'm not sure ease of use is that great so no compelling reason to switch right now.

Yamaha-The drums are poor with the exception of the new Genos revo drums. Genos is overpriced for me. They also refuse to put in my favorite fingering (Uncle Dave agrees with this-one finger makes a major, a C+Eb=minor, C+b=maj7, C+Bb=C7). I am used to this and can't do without it so that rules them out in my book. I don't really like the registrations but I could learn to live with that.

If I had to pic something today for an all around arranger
to fit my current needs it would be another Yamaha SX700..

Because you like Yamaha, that makes sense-you could add an external harmony unit and you're not paying for what you don't use.