understand but this could sacrifice security for user friendliness.
No, there isn't any sacrifice of security.
BIP39 is considered easier to read/write because it contains actual words that can be read and write without mistake. Like the word "legal" in your example. The user already knows this word and its spelling. So they just write it in an instant.
I agree up to a point. While English words may be easier for English speakers, others may have little clue how to spell (write) them. Also, some words in the BIP39 dictionary are mistake-prone, e.g. chief and chef.
However, your result doesn't contain anything that is easy to read or write like "iqogu". It is not a word, but just random letters. So the user has to write them down one by one with a high chance of mistake.
In other words there is no difference between "sylui duboli kufuzu..." and "C85AFBACCF3E1EE40...." in how easy it is to read or write.
Not exactly. They are not completely random letters. There is a syllabic structure/pattern that a string follows.
Now that it's been mentioned I just realised OP said an easier way to write private keys and the words ain't even something that's understandable or could be memorised.
Correct.
As far as the algorithm goes, you don't describe it anywhere, but my guess is that you are using base-120 with 2-character digits.
To be precise: base-126 with 2-character digits (except for single/1 character vowels).
Thank you all for sharing your opinions.