@Ox_ First of all, thanks for spending the time to write out some well-thought criticism. It's a thousand times better than some half-assed comment and I'm glad that yours is the first I've received.
This project is in its infancy and I'm updating it regularly. I made it because it's something that I personally use on a daily basis and I plan on adding all sorts of functionality. The initial version you see here is the absolute bare-minimum and will improve over time. As I need more from the project, I'll add it. It'd be great if you could list some of the programs you mentioned to be better so I can hopefully incorporate some of their aspects into this one.
You're absolutely right that the GUI isn't responsive, I haven't gotten around incorporating threading and it's something I'd like to do once the basics are fleshed out because it's not like the program is doing much at the moment. I'd like to have a skeleton before I move onto the organs.
Regex is on the table but not a high priority because I personally never use it. Now that you've made your comment, I might just push it up the list since at least you seem to find it to be of importance.
Your function idea is actually a good one but would probably require me to write my own parser which is kind of overkill for something that's supposed to primarily search for instances of strings. I'd even bring up your argument that there's other programs to do that for you but they generally include a suite of other tools that you just don't need. It's like editing an XML, JSON, or CVS file with an IDE, and that's exactly why I started developing this project. It's still a good idea that I'll most likely end up bringing into fruition just to see if it fits well into the idea of what this is supposed to be.
To conclude, it's never a bad thing to have options lol. Whether someone wants to use this project is up to them and they're free to use other ones if it doesn't suit their tastes. It's also open source so they can go ahead add features and changes themselves if they desire. Honestly, this project is primarily for me and my needs, but I'd still like to make it available for anyone who'd ever want to utilize it. Again, thanks for your criticisms.