Mortgage rate hikes on top of already high prices are pushing out many would-be homebuyers.  But as buyer competition cools, home sellers are starting to losing their leverage. Fredrik Eklund says homebuyers now have more power to negotiate on home deals.  Loading Something is loading. A vibe shift is happening in the real estate market. Over the past few years, a lack of housing inventory has resulted in intense bidding wars that have kept home prices at historic highs. But as mortgage rate hikes push out many would-be buyers, competition is cooling — and that means sellers are losing their leverage.  As market dynamics begin to change, NYC-based real estate…