Perhaps:
I would be (or: I am) very interested in learning your opinion of this theory. I look forward to (receiving) your (kind) response.

Vielleicht "I am very pleased to hear your opinion..."

oder "I (honestly) appreciate your opinion" oder so ähnlich.

@ all

Danke an alle, das hört sich schon mal sehr gut an, weitere Vorschläge natürlich jederzeit willkommen!!!

@ #2
geht das, wenn ich sage: "As I am very interested in learning your opinion on this theory, I look forward to receiving your response."?

Heißt das denn ...look forward to RECEIVING your opinion
oder to RECEIVE your opinion?
Danke

...to receiving is correct. The rule is actually simple: verb + preposition (here to) is followed by the gerund, usually called today the "ing form". A bit confusing sometimes because in English the infinitive is formed with "to". Try and find time to read up on it.

I'm anxious to hear your opinion.

voilà:
Honestly appreciating your opinion, I look forward to receiving your response

Hat jemand ne bessre idee, nichts wie kommentieren^^