Some encouragement, perhaps.
I started using Textpad with 4.72, after a couple years of using a freeware editor called PFE (Professional Editor), paid for it at 4.75 (I think), and have spent so much time working with it, I never considered upgrading, for fear of it turning into something like one of
Micro$not's infamous "downgrades".
I apologize for doubting! 5.0 is great for me!
What I do:
Large and small text-to-csv data files. One of my recent ones was a complete Webster's Unabridged, converted to MySQL driven by a search page that allows wildcards in searches. (regexp to follow, when I get a bigger Round-Tuit)
Some of the files have been 7-15 megabytes in length, and Textpad's combination of regexp and macros is the only editor I've found useful, short of chasing a degree in using Emacs.

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I turn large and small text files (books) into HTML pages. From short stories like Sherlock Holmes, to the more adventurous, like a fairly decent copy of "History Of The Decline And Fall Of The Roman Empire" By Edward Gibbons. Yes, all 6 books, all 9 megabytes. (two weeks work in my spare time)
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It's also my daily HTML editor, used for 99% of that work.
With regards to buttons/customization, it totally missed me. I have written and saved to file many of the macros I use constantly. I find saving them and assigning key sequences for them, much faster as my hands stay on the keyboard, where they belong. I also have written 2 extensive clip libraries for HTML which let me drop in most of the page, and other templates I need.
"Buttons" would require more reliance on the mouse, which just seems to slow things down. I mean, how many people would hire a two-fingered typist? That seems to be what you're doing by relying on the mouse, rather than the keyboard.
Anyway, my forst post on this forum, and I gotta say thanks for an upgrade that kept to what I valued and loved in the original. Carry on.
Fred