I have experienced this type of "lethargy" that you mentioned, bro Meor. Some years back, there was a feeling of "been-there-done-that" with my watch collection (although mine was but a pebble compared to your mountain of a collection accumulated over the years), so I hit the "reset" button and cleared the collection sans a few pieces that I really liked. Thereafter, I tried to keep the collection to a manageable 7-10 pieces; so I would clear off a piece or two when I added in another new piece. I found that the self-imposed quantity control ensured that the pieces in the winders rightfully earned their wrist times and stories over time, all pun intended. Sometimes, I would buy a piece for its review in my blog, and would flip it immediately thereafter- so my blog was like a transit visitation for such watches.
This lethargic feeling would eventually be cured when a unique piece hits the market, no worries; but in the meantime, if you refrain from adding new pieces that don't truly speak to you, it'd help not to aggravate that adverse feeling.
Another half-way house remedy that had helped me, was to not procure the grail piece that I had in mind. I looked at it from time to time, but I refrain myself from getting it for real. This way, I kind of tell myself that I am still travelling in the journey towards that grail that I had in mind, and that I would stay contented when I have added that piece into my winder. Until that time, I would continue sampling other watches, but the quantity imposition remains. Just my 2 sen.