Pinball machines have come a long way from the chimes and electromechanical era. Sound, ramps, multi-ball, multiple flippers, toys/gadgets, ball locks, magnets, DMDs, LEDs, subways, cannons, programmable music. . . so many great features that can add to and make the game more enjoyable.

Is there room for any more improvement? What could be the next big thing to enhance the game?

Cameras strategically placed in/around the playfield is an idea -- this way you can record/review a good ball or game similar to video games.

Complete code, properly working toys, etc. are always nice. . .

Other thoughts/ideas on the next big thing in pinball?

Those would be much too easy to drain. . .

While cutting grass this afternoon I thought about voice activation. . . "Hey Pinball, Start Game."
You could ask the machine to do all sorts of things for you like look stuff up on the web, set timers/reminders, etc. I suppose you could just use one of those Googlie home things as a topper. . .

That is like saying Smart Phones mucked up phone calls. . . while I agree sometimes simpler is better I will take my Indiana Jones over Joker Poker most days of the week. TNA has a lot going for it but I like playing some of the classic tables just as much.