I just pre-ordered the S8+. I also am NO fan of the stupid "edge." You do have to bear in mind that it's what allows Samsung to fit a bigger screen in a thinner ("less wide") phone, though. There is a bit of a difference between the S8 and S7 edges, though -- indeed, the S8 edges aren't as "extreme" as the S7 edge.
The benefits? With the S8+, you do get some extra screen real estate. The actual width of the screen is either the same or perhaps even a hair less wide on the S8+ than the S7 Edge, but the difference is negligible.
As a fan of Samsung's "S-View" case, the new equivalent is actually similar to the old "clear view cover," but with a horizontal stand capability that should be quite useful. I'll definitely get one of those.
One of the big advantages will be Bluetooth version 5, which should use less power, give you far more range, and allow you to connect two different devices at the same time. That could be useful. And there are some other significant "future proof" advantages -- new technologies that are in our future, and it'll be ready for them when they get here. Also, there will be 64GB of RAM, which should help keep things running quickly.
Another thing to consider are the promotions -- you usually see the VR headset, but I could care less about that. What I'll definitely take advantage of is the offer to get a set of wireless Bluetooth headphones and a 256GB MicroSD card for only $99 -- I'm definitely going to go for that. Note that you truly have to pre-order an S8 phone, "with service," in order to qualify for the promotions. Best Buy is giving you $100 off in the deal, too, so that's where I pre-ordered mine.
In the end, if you haven't already, head down to your local Best Buy store and check the S8 and the S8+ in person -- they have them on display, and you can play around with them quite a bit. "Swipe up" in order to get to all of the apps, then go to town and play with the phones. You might find stuff you like, maybe not -- but go check them out!