A lot of topics now are regurgitated or just talking about the same ol' things, but I can't think of one place that is 10+ years old that doesn't suffer from this. You could go as far as the older generation, what do they talk about? Usually, the same thing over and over. Maybe, they are reliving through you, talking about their glory days or just days they remember fondly. I'd even argue you wouldn't even need to go as far as the older generation it was just easier to make the point. We all talk about the same things everyday. I, you and everyone reading this post. Its only when you get many different perspectives that you get a discussion. However, a lot of things have already been discussed, however that doesn't mean there's not any new input. People change, ideas change and perception changes day to day.
I've personally seen Bitcoin go from something which is outright denounced on sight by everyone I meet, to the more computer inclined people only talking about it, to pretty much everyone I have ever known talk about it at some point. Alright, its usually still with scepticism, but 10 years from now we might have a discussion about the same thing, but with a different perception. They might in fact trust it more, and have new input.
So, yeah same sort of discussions, but a shift in mentality, new ideas or ways of thinking about something is all part of the evolution of Bitcoin and the forum.
New ideas are presented every day. This might get a lot of hate, because generally the hostility towards altcoins is a rather frequent opinion expressed (not without its justifications) but the altcoins are indeed new ideas. Bitcoin isn't perfect, and we have altcoins attempting every day to improve on that. Obviously, that doesn't mean that a lot of them aren't a shower of shit though.
We've got mining changing every day, the fight against the rising costs of mining, to the point that the general user like me and you will be priced out, and dedicated mining companies are all to remain. New hardware, new ideas or just different ways of going about things like group "solo" mining where you get a small group of people, point all their miners to the same custom pool and share the reward rather than joining a much larger pool or solo mining themselves. These are just examples, but before you were either pool mining or solo mining, because the costs of such were lower. Now, people are looking for ways to get into mining before its too late (due to costs) and maximising their profits and chances which usually means banding together in some way.
New ideas and mini discussions floating all around us. Unfortunately at times it does seem like we are wading through shite to get there though. This does come with popularity and ease of access. Bitcoin software is so much easier to use these days. 10 years ago, it was hard to setup a wallet, now its practically like any other bank account you might have for more traditional monies.
Twitter has good discussions, just like bitcointalk have. You just need to know how to navigate in this forum, which is a lot harder than in Twitter or Facebook etc...
I must be getting old. I absolutely despise Twitter and how its laid out. I wouldn't know as I don't have twitter any more, but didn't they go away from chronological sorting of ports? To me that's counter intuitive. I'm sure it can be configured, but I'm sure I remember it going to the default not being sorted by new or something. It has been a few years though.
I'm sure there's some great discussion elsewhere. I won't say there isn't, but if you want a discussion where's the first place that pops into your mind? It has to be here. Reddit and Twitter I see more as news and reaction to the new, rather than getting into the very ins and outs of Bitcoin or related spaces.