Excellent post with your impressions of the S8+. Pretty much mirrors my thoughts on the phone exactly. I do love my 7 Plus and will be holding on to it for a while but Samsung nailed it with this phone. I miss the speakers of the 7 Plus also, as well as the dual camera setup, but as a complete package I feel the S8+ is the superior device. The speaker is definitely an improvement over the S7 Edge, so I wouldn't quite call it garbage, but it is a slight letdown after using a 7 Plus for the last few months.
My only complaint so far is some lag experienced when sliding left to use Bixby. I know, I'm probably one of the 3 people that use Bixby, but I kinda like it. Other than that, the software is quite nice, leaps and bounds beyond any other Samsung I have used, and I've owned all of the Notes except the first one and all of the S series going back to the S2. Other than the Bixby issue I haven't noticed even a hint of lag and that speaks volumes to how far Samsung has come with Touchwiz, Samsung Experience, or whatever they are calling it now.