The new 7.3 10speed with 4.30s will smoke your old 6.2. But a diesel will walk both of them like a dog.
Do you want to keep speed compared to your 6.2 but still be tapped out on big grades and coasting down the other side? Or do you want to roll up hill with ease at half the rpm’s and more on tap if you want and cruise down the other side without using the fat pedal?
Personally I’d keep the ole 6.2 this year and wait for some sucker losing his ___ in a year or 2 if I didn’t NEED to upgrade or budget is a big consideration.
On the other hand, your old gasser will never be worth more than it is now, since prices are dropping in that category of trucks. Diesels have leveled out a bit too but nothing like the gas pigs.