Note coma is a linear off axis aberration so the 31mm Nagler with 42mm field stop diameter will show more coma than a 35mm Panoptic with 38.7mm field stop diameter in the same telescope. Also you will likely see the coma more easily with the 31NT5 since it will be magnified more. A Paracorr really does clean things up nicely but at the expense of weight.
Consider also the 26mm Nagler with a 35mm field stop diameter as it is almost the same size and has the same weight as the 35P but it does have less eye relief if that is an issue.
Have a look at
http://www.televue.com/engine/TV3_page.asp?id=28 and you will see that the 35P and 20NT5 are in the same Parfocal group and are a nice combination. (The 20NT5 also combines well with the 31NT5 even though not parfocal with it. You can also see (column F) that the 26NT5 and 17NT4 are also almost parfocal. This also means the paired parfocal eyepieces mentioned have the same Paracorr setting on the tuneable top.
One last option is the 21E which has a 36.2mm field stop diameter but weights slightly more than the 31NT5. Note you can get the 35P+20NT5 for a few dollars less that the cost of the 21E.
The 35P will give you a 'large' exit pupil but if your sky is not too bright it will be fine. Also if you are only using it as a low power scanning/finder eyepiece it will also be fine with the larger exit pupil. The 31NT5 is one of the best eyepieces Tele Vue has made and is a fine performer in many telescopes and you do get that beautiful 82 degree apparent field. The 35mm Pan is also a very good eyepiece with excellent eye relief and if you prefer 68deg apparent fields would be the eyepiece of choice.
Note if you wear glasses when observing the 35P will be more comfortable and you will be able to see the entire field more easily. Again see also the Tele Vue specs for eye relief figures.
Whatever you choose, enjoy!