I'm kind of intrigued by the concept of a TF2 map with Quake-like design theory. After all, TF2 did start as a quake mod.
Having said that, there is undoubtedly a reason that the level design of the Team Fortress games has changed so much since the days of it being a quake mod. As messing around said, it just plain and simple favors some classes over other ones.
So, the way I see it, you have two options:
A- Cut down your sightlines and make it closer to a standard TF2 map. If you want your map to be played seriously, this is what I'd go with.
B- Own up to the imbalances and just keep doing what you're doing. If you don't care if the map isn't perfectly serious and just want to stick with the original design concept, I'd go with this route.
Personally, I'd be way more interested in seeing where this would go if you pick option B, but it's your choice, obviously.