[Android Q&A, Help & Troubleshooting] Clues:
I've installed over 50 editors and reviewed 100s in the Play Store... none of them do everything I was looking for. Maybe I missed it.

Editor requirements:

Toolbars at the bottom.

Dark theme (option)

Dark paper / background

Autosave

Insert image (prefer in-line but thumbnail might be OK)

Formatting (bold/font/colors)

File Types = rtf or doc

Opens to last edited and in edit mode.

Trial/free version available for testing before purchase.

No pushy popups asking me to download other things.

Clipboard - easy to use.

Bonus:

Cross platform version in Windows (web version.ok)

Wont freak out if I use AI Keyboard to paste text.

Links - between docs / pages / to web.

Save as text only.

Save selection.

Send selection.

Clipboard history.

Undo history between edits.

No monthly/annual fees

Tags

Toolbars: App buttons should be configurable, always. Buttons for menu/bold/saveas/new could be at the top, bottom, left, right, or floating, per the user preference. I'm really disappointed android has not done more to assist users with reaching across their over sized screens. Almost no apps have this, and only a few place the controls in the obvious place = next to the keyboard = where the user is most likely to want to tap. S5 ships with quick screen sizing ability built in, seems Samsung is ahead on this one. And I don't think it's asking a lot, it's just a matter of moving the bar to a different place, it's too easy!

Theme: A dark theme uses less battery and is easier on my eyes, especially when it's dark out. The theme is the part around the edit area, strictly speaking. This would include all menu's and toolbars. There are great editors out there with dark themes and dark paper but the menu's open super bright, and whats worse is they'll put light gray text on them in wee little fonts with lots of space to make it bigger... and then ask for $$? No.

Paper: A dark paper is super easy to read in any lighting conditions, and uses less battery to display (the display takes 50%+ of most phones battery power) When printing, white paper is best because it is cheap and readily available, and printers are not generally equipped to print light colors on dark paper. Since most people are addicted to printing things they look at 0-1 times, we may be stuck with this for a while. In any case, I want dark paper. This has been a feature in editors for a long long time but is mostly missing from Android.

Autosave: This is a must. If it uses the "save every 10 seconds", it should also save on exit without prompting if I close in only 5s.

Insert image: My preference would be to have text above and below, not around, and not as a layer that is under typed text. If it's attached as a thumbnail, it should be easy to see and tap to zoom.

File Types: My favorite is RTF. It's been around a long time, compatible with most things. Any fairly common windows format is fine like doc or even pdf. I want to avoid special formats that wont work anywhere else. I don't mind if the program has this ability but if it cannot open/save in other formats by default, I'm not interested.

Opening: It should open to the last document opened, and ready to continue typing. If it opens to the home page, then I want to see a recent list with the last edited on top, and one tap to edit. I found some really nice apps that took 5-6 taps to edit a doc. For example, Evernote opens to the home page, you tap to view, scroll to where you want to type, tap and ... nothing.... you have to tap MENU and then some symbol for edit, and then you start typing and it's not typing in the right place, it moved to the top or the bottom or whatever... terrible app IMO.

Fees: I have dropbox and other storage already, I'd rather not sign up for yet another one. Many apps work with existing sharing services just fine, while others require payments for this, generally 4-8 per month. I'm only willing to pay if it is the only one that meets all my other requirements, and it has to be the super ultimate editor and really amazing too.