I would give it more than one ride before you decide.
I did a 2.5 hour ride up to Iowa and it was ok, but then did a 5 hour ride home and thought my balls were going to burst into flame (not as much fun as it sounds), that's enough for me. I made this post after riding home that weekend.
The seat is infinitely more comfortable on long rides than the stock seat.
Maybe for your butt, but not for mine. It's narrow in the front, which makes for a lot of pressure in a small area and if I'm in front, it's taller because there is a rise in the seat near the front. This makes me more tiptoed in a parking lot situation, not something I am fond of on a 700 lb bike which is frequently heavily loaded. Not saying the Sargent is a bad seat, it just doesn't work for me.
I didn't really experience the "pitchy" feeling you experienced, but any change in ergonomics will make the bike feel different.
It's not something you notice when you are comfortable with or used to the bike, more something that is noticed when you switch from another bike to this one, in my case, my 2005 FZ1, which is chain drive and doesn't pitch forward heavily when rolling off the throttle. Riding the FZ1 for 1500 miles to MOAR and back, then jumping on the C14 made me aware of pitching, as did a PM from someone. I have resolved to smooth out the throttle transitions to allay this issue when possible.
My comment about the Sargent being more comfortable than the stock is related to pain, not heat. If I were out near you I would let you try out my Corbin. I almost made it out there this past weekend, I had considered riding to Iowa to see family. The Corbin doesn't make me as hot as either the stock seat or the Sargent, although on very rough roads it can beat you up, something the Sargent doesn't do.
Thanks for explaining what you mean by pitchy, now I get what you are saying.
I truly understand what you are experiencing though. I too feel the heat on long rides in hot weather, it is the main reason I decided to try the Corbin after using the Sargent. I truly love the comfort of the Sargent, I just wanted to see if the Corbin helped with the heat issue.
I have the LD Comfort riding pants and various Underarmour and underwear like them, they all help, to a degree. I usually ride in a pair of AVG Telluride pants and they help insulate me from the bike a bit more than jeans do. I often simply wear a pair of lightweight unpadded mountain bike shorts along with Underarmour underwear, or even regular boxers under them so I can remove the pants and put on a pair of flip flops if I want to be off the bike for a while. I think the riding pants did the most to help combat the heat for me.
I seriously love the comfort of the Sargent although I believe it could be a slight touch firmer than it is. It broke in a bit more than desired. The Corbin is decent on the interstate but on a ride across West Virginia on small back roads and route 50, it had me in serious pain due to the bumps. My wife prefers the Corbin unfortunately since it prevents her form sliding forward. She also ends up with a sore posterior with it though. I will have to take her on a long trip to see if her opinion changes.
Good luck.