Meaning of 「これはこれで」, and the difference between it and 「それはそれとして」

Question

I came across the following lines.

・・・俺としては、下駄箱の中に手紙が入っているみたいなほうが好みだった。でもこれはこれで、少なくとも相手が積極的だってことはわかる。

I am wondering about the meaning of 「これはこれで」 here. As one might expect, it does not have any entries in the dictionaries that I use. However, it seems to me to mean something along the lines of "that aside".

If this is the case, what would be the difference between 「これはこれで」 and the 「それはそれとして」 below?

・・・まあ、それはそれとして、正解の答えがわかっても、どうすればあの「sprachgefühl」が身につけられるかという問題が残っています。

They both appear to have similar meanings.

Or would the sentence perhaps be better interpreted as such?

[これは] [これで少なくとも {相手が積極的だ} ってことはわかる]。

Answer 1

それはそれとして means "that aside, ..." "apart form that, ..."
Compare:
これはこれとして "that aside, ..." "setting this apart, ..." "apart from this, ..."

The これはこれで (≒ (これは)これなりに) here means "This (is good/okay, etc.) in its own way."
Compare:
それはそれで/(それは)それなりに = "That (is good/okay etc.) in its own way."
彼は彼で/(彼は)彼なりに =　"He (is trying hard / doing his best, etc.) in his own way."

I would parse your sentence this way:

[これはこれで][少なくとも{「相手が積極的だ」ってことは}]わかる。

Answer 2

I think these are shifting between the topics.

「それはそれとして」 When we use this, we mean 'leaving that topic as it is, now let's talk about this instead.'

「これはこれで」 When we use this, we mean 'whatever else is there, this one is...'

「それはそうなんだが」
「あれもそうなんだけど」
could also be used to shift the topic, to talk about something that is on the plate in front of the speaker.