So here is my feedback, and why I think this layout isn't going to be great for TF2 gameplay. Pictures are informative:
Also, to guard myself from being ignored due to "childishness", let me just say that I'm 100% completely serious with this image. I could have easily made a joke out of it, but I did not.
Edit: my point is the easiest shot to make as a sniper is on a target on flat ground, with both sniper and target on the same elevation, with no obstacles.
Distance is not a factor unless taken to extremes, personally I find ~768 units and beyond to be optimal sniping range, but nothing is stopping me from taking shots (successfully) at closer range too, it's just not preferred as it's more dangerous.
What you have is a map where all player will be on the same elevation, on completely flat ground with no obstacles. As it stands, every bit of road you have there is a viable sniping position, depending on where the target is.
Not to mention, this isn't just a sniper issue. Flat ground is notoriously boring to fight on as any class. There is absolutely nothing you can do in a fight to gain a positioning advantage, which devolves the fight into a pure aim battle rather than a tactical + aim battle.