This is a wish for a different solution to the problem described in bug 89576 aka
«word completion doesn't use latter part of word to suggest better hint»:

In Kate and Kwrite, when placing the cursor inside a word, word completion only considers the first part of the word (as delimited by the cursor) to suggest completions. I think this is totally fine.
    However, after choosing a completion, the second half is still there, as a suffix to the word I just chose to complete. I find myself always deleting that leftover suffix. I want it to be deleted automatically.

Reproducible: Always

Steps to Reproduce:
1. in Kate, write (without quotes) the names "Jensen" and "Hansen" on separate lines
2. mark "Han" and overwrite it with "Jen"
3. if you have word completion enabled after 3 characters, Kate will now suggest that you mean "Jensen". Let it complete that for you.

Actual Results:  
Kate has now invented the name "Jensensen" for you.

Expected Results:  
Just "Jensen" would be fine.

By not deleting the leftover suffix, Kate is taking word completion to a whole new level by inventing new words. This is NOT behavior you need or expect from a «word completion» feature.

How this wish is a prerequisite to wish 89576:
The leftover suffix has to be deleted anyway. Taking the second part of the word into account «to suggest better hint» can be implemented later.

How I don't like wish 89576:
I'm not sure I even want a «better hint», if that means narrowing the search. Shouldn't "Jenny" be considered for completion of "Jen" regardless of "sen" being after the cursor? I don't know. One can always narrow the search further (exclude Jenny) by typing more characters.