Mfcttrf

I can't seem to get a good grasp of it. I found a few example sentences and read on weblio that it means: to think (something) is improper; to question; to have a problem with.

From the sentences I read, most of them were translated as "I doubt that..." or "I'm not sure about that".


There is this line that I found in a manga, with 2 boys having a banter:

A says: 死ね。

B replies: すぐ死ねって言うのどうかと思う~☆ (yes his line has those symbols, which I can only think that he has a playful tone and is mocking A)

"I doubt that I will drop dead right away"/ " Die quickly? I'm not so sure about that"
Do these translations make sense?

「どうかと思う」 is a roundabout and indirect way of expressing one's somewhat negative opinion or impression of an action, situation, tendency, etc.

It is indirect for using the word 「どうか」 ("how is it") instead of directly saying "I don't like it.", "I think it's bad.", etc.

A more direct version of 「どうかと思う」 would be 「あまり感心かんしんしない」 ("I am not so impressed.") and that would be one way to translate 「どうかと思う」.

Other possible translations would include:

"I kinda wonder about ~~."

"I don't think it's so good."

"I find it less than ideal."

Whatever fits the best in the target language is the best translation. One will not arrive at it just by staring at the phrase 「どうかと思う」 as it is not a direct expression.

Finally,

A says: 死ね。

B replies: すぐ死ねって言うのどうかと思う~☆

"I doubt that I will drop dead right away"/ " Die quickly? I'm not so sure about that" Do these translations make sense?

For a translation, that is O.K. because translation is an art, but if you really want to understand B's line, it is said about the fact that A said what he said facilely. The 「の」 in 「言うの」 is a nominalizer.

The 「どうかと思う」 is said about A's way of speaking, which uses a serious phrase like 「死ね」 too easily. It is not said about whether B will actually die soon.

どう can, colloquially, be used to express one's opinion of a thing being "questionable", or "dubious", without outwardly nor directly criticizing it either.
It takes this meaning when used more "affirmatively" in the sentence, a bit like interrogative words may take a critical meaning when put in rethorical questions in a language like English.

In other words, akin to how What do you say ? asks a genuine interrogation while What do you think you're saying ? indirectly states a reproach, どういうことですか？
("What's this") most likely asks what something is while どういうことなんだよ！ can express critical bewilderment ("What the **** is this !?").

Similarly, people will often utter どうかな to express (inwardly) doubt about the validity / reasonability / etc of something. When expressed outwardly, ○○どうかな can become for example ○○どうかよ！ to prompt someone to reflect on the validity / ethics / etc of ○○.

So in your example, すぐ死ねって言うこと is what's being questioned by the speaker. You could replace the sentence by すぐ死ねって言うのどうかよ or すぐ死ねって言うのどうなんだよ and it'll be a harsh reproach of "instantly saying 'die!'". すぐ死ねって言うのどうかと思う or even more explicitly すぐ死ねって言うのどうかと個人的に思う / すぐ死ねって言うのどうかと個人的に思うけど / etc instead conveys the speaker's mixed feelings about "instantly saying 'die!'" in a more indirect thus soft and gentle way.

Eventually the use ~☆ hints that he|she is making his criticism as lightweight and indecisive as possible. I'd wager he|she doesn't mind it much eventually, is just lightheartedly bantering, or is quite afraid of and cautious not to ire the person who said "死ね。" for example.

I'm not sure what to think about instantly saying 'die' ;)

What's up with that immediately saying 'die' :/

for example would sound like legitimate translations to me, especially tone-wise.

To be clear, the 大辞泉 lists up "having doubts, not being sure" and "finding it odd, distancing oneself with" as 2 separate definitions for どうか.
My above explanation mixes these two, as I think the root feeling is basically the same, and I hoped for it to rather give a intuitive grasp or "gut feeling" of what the idiom can express, generally, than restricted definitions or translations.