In the context of someone passing away, would あなたがこいしいです convey the same meaning as あなたが恋しいです
Or does the use of Kanji over Hiragana imply something more?
In the context of someone passing away, would あなたがこいしいです convey the same meaning as あなたが恋しいです
Or does the use of Kanji over Hiragana imply something more?
Strictly speaking, the answer to your question is that there is no semantic difference in the specific case of こいしい and 恋しい. In theory, a word can be understood when written in any Japanese script, even if it is not the most commonly used or most familiar. It does not usually alter the semantic content of the word as a lexical item, although it can.
That is not to say that there is no difference at all between scripts. Choice of which script to use when writing a Japanese word can convey subtle nuances or overtones. They don't usually change the overall meaning, but can add a certain 'color' to the term, if I can use that analogy. The most well known example of this is probably the word 'manga'.
漫画 マンガ まんが
It is often written in any of the three scripts and there is an ongoing debate about what difference (if any) this might convey. The argument goes that when written in kanji it has a more formal, 'adult' feel to it, whereas when written in kana it might appeal more to children. In Japan children learn Hiragana first, then Katakana, then kanji (although there may be some overlap). Therefore children often read manga in kana only or with kana attached as furigana. There is no real consensus on this issue and it has been discussed in academic papers too. For example, Robertson (2015) listed the following characteristics associated with the different scripts:
As mentioned, it is an ongoing debate. Most words tend to use only one of the three scripts. Notable exceptions include onomatopoeic words, plants, animals, etc, which are often written in either Hiragana or Katakana. But it's far more common for a word to have only one standard script usage. However, since you asked specifically about the semantic difference between こいしい and 恋しい, the answer to your question is that they are essentially the same. Hope that helps.
Or does the use of Kanji over Hirigana imply something more
First of all, do you know 恋しい is normally written using kanji? The kanji 恋 is not difficult. An online corpus (BCCWJ) has 140 examples of 恋しい and only 4 examples of こいしい. Among those 4 examples, one was used to show the reading of 恋しい, and two were written by a nonnative speaker who did not know many kanji.
Therefore, "the use of kanji" implies nothing. It's just the standard way for a native speaker to write this word. If you are a beginner and did not know this fact, you can stop reading this answer here.
That said, a few native speakers may intentionally choose to write this as こいしい in this context. I can think of two reasons.
First, owing to the image of hiragana described in kandyman's answer, こいしい looks more feminine or gentle than 恋しい. Although the difference is subtle, the intentional use of こいしい here may make the sentence look less formal and a bit more intimate/emotional.
Second, while it's perfectly fine to use the word 恋しい in this context, 恋 is the kanji that primarily means "romance" or "(romantic) love". Some people may want to avoid this connotation by removing the appearance of the kanij 恋. By doing so, it may imply "I'm not saying I was in love with you, but I miss you anyway". (Again, even if you said 恋しい using kanji, no one would misunderstand in this context. Don't take this as a rule or a widely-recognized convention.) For similar examples, see: Why did Asahi Shinbun write "子{こ}ども" instead of "子供{こども}" in this headline? and Why is hiragana used in the middle of this compound word? (障害者 vs 障がい者)
Related: