[parkher]

uboot,

It seems that there is a slight possibility of messing a rooted T1 up by doing nothing:
there was at least one report that the recovery package was needed after the battery ran out possibly while T1 was in the sleep mode without a proper shut down - some apps were crashing after that, the recovery package was needed to fix the problem.

Fanchee,

You are describing a non-rooted T1.
If your T1 is rooted, you can use your own nested directory structure for your books, no need to keep them all together.
I have a 32 GB card full of books in my T1, maybe 100,000 books on the card, so I have folders for languages, for authors or multi-author collections, authors are split into first letters, then inside the letter "A" only the authors whose last name begins with "A", then the folder for that author, then a subfolder for each series (if there are any), etc.
This way you have your library in the way you like, not relying upon artificial logical collections.

To navigate this folder structure you could use an android file manager, but you don't have to. Both FBReader and Cool Reader 3 have their own integrated file managers. Especially suitable is Cool Reader as you can use page up/ page down with the T1 buttons, no need for scrolling.
You start Cool Reader, and you never leave it: you read books, you open new books, you get to the list of the last read books and switch to a different book, you use dictionaries, etc. - never leaving Cool Reader.

With Cool Reader, I also can use fonts I like at exact sizes I like, interline spacing I like, etc.
The most important - I can set margins I like. Can you believe it - the Sony reader does not allow to change margins at all! You are stuck with the impossibly tiny ones. And if you attempt using cropping - the margins may disappear altogether.
With Cool Reader, I can set any margins I want: at least more reasonable 4 mm, or in landscape mode - 1.5 cm or more on each side.