An interesting collection of eyepieces, and yes you really don't need much more.
My bias thoughts are that the TOA150 represents the pinnacle of refractors today, and it comes with a hefty price tag. I wouldn't potentially hamstring it with anything but the best quality optics with generous fields of view.
It appears you have various refractors for imaging purposes regarding image scale, but I would invest in some Nikon or Docter, Pentax XW's or Delos, or Ethos eyepieces to compliment that visual optical train. Also a premium diagonal from Baader, Astrophysics or Tele Vue if you don't have one already.
Yes, it is not cheap to invest in imaging and visual top of the line gear, but to extract the best from your TOA I would not do it any other way. I've read that the Nagler zoom is great but apparently falls short a bit optically compared to fixed focal lengths, but others can confirm that not me.
At the very least, I would switch out the AT2x barlow for a TV 2" powermate. I think the powermates are a bit sharper than barlows in general. I loved using powermates more than TV barlows.
I can't comment on the 19mm Pan specifically, but I have seen a 31 nagler outperform a 35 panoptic for apparent sharpness. For that reason alone I would get a 17.3 Delos over the 19 pan.
Just my 2cents...