Nice catch.

Thanks Jim, but I can't take the credit - a Jisho user reported it to me :)

I think
誰かを代理にせず、あなた自身が行って話したほうが良いでしょう。
Sounds better.
話すほうがよい sounds very wrong to me.

And as always:
This is neither mother-tongue, nor a Languages stated inside your profile. You might think about deleting Japanese sentence contributions. I think contributions in your mother-tongue are much more valuable :)

@MisterTrouser - I think you possibly missed the point of kimtaro's edit, which was to amend a clear 変換ミス in the original (wrong じしん), and in the circumstances was quite appropriate. The original came from the Tanaka Corpus. See https://www.edrdg.org/wiki/index.php/Tanaka_Corpus and in particular the warning at the end.

Although the Japanese sentences in the Corpus are from Japanese sources, many are rather clumsy and (still) have significant numbers of errors.

Both 話すほうが良い and 話すほうがよい can be found in the Google Japanese n-grams corpus in reasonable quantities. 話したほうが良い is more common, but tense may be an issue there.

> many are rather clumsy and (still) have significant numbers of errors
Wouldn't that be an indicator not to use those sentences?

> but tense may be an issue there.
What do you mean by that? Because 話した？

>> many are rather clumsy and (still) have significant numbers of errors
> Wouldn't that be an indicator not to use those sentences?
Most of them are OK, and in the absence of any alternative source I think they're worth persevering with.

>> but tense may be an issue there.
> What do you mean by that? Because 話した？

I'm aware the ほうが良い is usually associated with the past tense, but since I'm seeing it used with non-past I'm reluctant to change it. I'll run it past an NSJ when I get a chance.