I see you uploaded some new screens
You don't want repetitive patterns it throws off the eye, the second screenshot with the bus stop like entity is an example of that, you should study asymmetry, it's basically the mixture of symmetrical objects like a building with asymmetrical objects like props or uneven terrain road ect, the buildings are also more or less the same height, it should really be mixed up a bit in size.
Large flat areas is also a very bad design idea, the road is another example, it's a common thing I have seen with FPSC in general, roads aren't flat, roads in general slope off to the sides for water run off. To compensate for this and to throw off the symmetry a road island with a couple of trees or signage even obscuring the player view to only a few meters would help break up symmetry.
Instead of a plain road adding a texture with painted road markings on it will also help.
Your in a build up area, there is a solitary green light in the background, build up areas is brightly lit at night or dusk with street lights, neon signage even buildings should have a light or two on.
What did you put on top of the roofs ? There is far too much of it, it looks out of place too, consider what you would generally find on a roof and only keep to those props.
I don't see any focal points in the level, a focal point is for example a large detailed old tree in your level that draws the players attention, for example you have hidden some ammo there, a flickering light in a shop window to denote the path the player needs to follow.
You have to remember that if you create an open world, unless you have a gps system in place to direct the player where he needs to go, you will have to find alternative means to direct the player where he needs to go even if it's an open world, aimlessly wondering around in the level trying to find out what you need to do is only going to fustrate the player into quitting very early on, just keep that in mind, focal points will help as well as other clues like audio.
Lastly be mindful of posting screenshots, by look of the screenshots provided it definitely looks incomplete, consider either only posting appropriate content of such a nature that is either complete or near completion, incomplete screenshots do more damage than good, yes you want to update you have done this or that, consider you are posting this on a much larger platform you need your A game here and only post when there is some thing worthwhile.
Instead of posting in game screenshots posting screenshots of content currently being worked on, even 3d model screen renders will work wonders to grab people's attention, instead of incomplete goodies.
Win7 pro, Intel 2500K @3.7ghz 660GTX 8gig ram 16tb HDD