Remington brought back the T4 before they went under and IMO their change from Microgroove to Ballard rifling improved the accuracy and versatility of the cartridge. If Ruger got all the CNC machines in the Marlin purchase I see no reason why they wouldn't continue building the T4.
I have a 68 JM straight stocked T4 and a 2 newer Remlin 45-70's. I really like both cartridges.
Winchesters Timber short barrel ported T4 wasn't popular I'd guess due of the barrel configuration. I have a friend who's wife bought one for him years ago. I've shot it and it's a LOUD beast compared to my Marlin. It's not as accurate either. If they did bring it back I doubt many people would pay $1500+ for one which is the average price of Winchester's (Miroku) levers these days.
Not sure about Henry introducing a T4. They've already got to many calibers and configurations now.
