Creating a messaging software/app... bad idea?

I think that instead of asking for a general advice regarding goo/bad ideas, you should focus on learning how to know whether it is good or bad.

There are lot of resources to help you validate your assumptions with as little investment as possible. There is always room for one more app. To be honest, I dislike Slack a lot. I am so happy with e-mail, it's decentralized, encrypted, inclusive. Slack just stripped all the good things of e-mails.

So, if you ask me, there is always something that can be done better.

I'd say it depends :) Do you have a target audience in mind? Would it be an app for synchronous or async communication? Would that be a client on top of other platforms or a standalone app?

The issue is that nothing is fundamentally broken with the existing messaging apps. So it would be a tough task to get people to switch over to your app.

What's the compelling factor?

If it helps, something is broken with messaging: too many clients. If I could message all the contacts I have scattered across 12 different networks from within one client, I would potentially pay for it.

I’ve found slack to be unorganized and their notifications totally messed up at times

That look like a pain point for you, maybe others feel the same.
When was the last time it messed up the notifications for you? What were you doing? Was it so bad that you stopped relying on notifications? Is that really a problem or just an annoyance that nobody really care?
You can answer all that and try to find out if other users feel the same, depending on that outcome you can decide what to do. Try to read "The Mom Test" it helps to validate ideas.

Would throwing another chat app on the market a bad idea? Thoughts?

This type of question can't be answered. Maybe we can give our opinions, which are pretty much worthless. Better would be to try to explore real world "chat" problems from real users and try to pinpoint if there is an opportunity there.

You should try to start with: https://rocket.chat/

It’s a open source slaxk

I'd also say it depends. If you make something that you genuinely enjoy using, you could be onto something.
I would say the best way would be to build a client on top of other apps, so that you, for example, collect all feeds from Slack, MS Teams, Twitter, Email into one "unified" interface, which helps organize it. At least, that would be helpful from my point of view. :)

I do wish there was an easier way to casually have chats with people.

Twitter kind of covers these for me, but it's not ideal. And I'm not sure if there is a real answer to this 'problem'.

It would be an uphill task. Are you focusing on enterprise/teams? If so, I'd actually put up some mocks and get some pre-sales to figure out if this is worth investing time into.

I'm not saying this is a good/bad idea but just that you can let the market decide. I made the mistake of investing a lot of time into something that didn't have too many takers in the end but I really learned how some people de-risk the process to an extent.

(I really liked Flexport's founder Ryan Petersen's podcast episode about approaching new ideas: https://www.youtube.com/watch?v=hjUs7o-TnjY)

You can think of a worse idea.

The worst ideas are usually the best. The best ideas are all taken. The average ideas.. those are actually the worst.

What do you want? A chat app to chat with your.... what?

Super-serve your own type of ppl.

Make a chat app you love.

Also, I don't think Slack considers themselves a chat app.