Keeping your birds occupied helps to not only avoid boredom but also decreases the chances of having 'behavioral' issues. Training is a great way to keep your birds occupied and in line with who's in charge.
It's just that too often people get a bird with expectations and when the bird doesn't meet them, they lose interest in the bird and neglect it. It's a LOT more common than you might think.
One of the things that ANNOYS me most is whenever I take Skittles out for walks in the summer time - the FIRST thing people say after compliment his beautiful feathers is 'does he talk?', like all bird talk - which isn't true. But they have this false belief that all birds talk, all birds do any trick and so on. They are all individual personalities and you have to go with what you get.
I see lots of videos about suns doing things I'd love to see Skittles do, but I doubt he would do those things given his personality. But I don't want a 'reflect-a-bird' I want an individual one. It just makes me appreciate Skittles more for being unique and what he does do, I appreciate it for what it is - his way of being him.
To be honest, I think talking birds can be overrated. Yes, they are hilarious and its so sweet to see - but you ask anyone with a talking bird - once they start to speak they tend to repeat that phrase or word over and over - and they pick up on naughty words cause anything said with 'emphasis' gets their attention. I use profanity too much to even want a talking bird. Granted, most of my profanity is when I'm on the phone, but it's not something I want Skittles repeating - especially if that person happens to visit.
The best thing I can suggest is observe your birds - find out their individual personalities and focus tricks and training based on that. Suns are highly intelligent and they do have the 'capability' to talk and do tricks - but not every sun will talk and not every sun will do tricks.