δεῖ ἄρα καὶ τὸν σύμβουλον σκοπεῖν ἆρα τεχνικός ἐστιν εἰς ἐκείνου θεραπείαν, οὗ ἕνεκα σκοπούμενοι σκοποῦμεν.
Why this redundancy: σκοπούμενοι σκοποῦμεν?
Not quite redundant. The middle turns it into a characterization of how they are conducting the investigation.
What is that characterization though? Reading through a bunch of Plato examples of both, I think that the middle implies some sort of internal mental consideration.
This comes out in Crito, I think. There Plato seems to use the middle when he means “we need to consider this matter”, and the active when he means “listen to what I have to say” or “let’s work through this together”.
σκοπεῖσθαι οὖν χρὴ ἡμᾶς εἴτε ταῦτα πρακτέον εἴτε μή
πῶς οὖν ἂν μετριώτατα σκοποίμεθα αὐτά;
σκόπει δή
καὶ τόνδε δὲ αὖ σκόπει
Σκοπῶμεν, ὦ ἀγαθέ, κοινῇ
σκόπει δὴ οὖν
Ἀλλ’ ὧδε σκόπει.
Σκόπει τοίνυν
Σκόπει γὰρ δή