Is this a good and balanced build?

[brominecraf]

https://pcpartpicker.com/list/LG9XCy

Would there be a potential bottleneck at 1440p gaming?

Is the cpu cooler enough for a higher overclock than you would get with the stock cooler?

 

[Candan]

That mobo isn't meant for gaming - especially if you're planning on buying a GTX 1080. Go with the Tomahawk instead.

Otherwise, you don't need a 700w PSU for that rig. 600w is MORE than enough. Even 550w

 

[Hellfire13]

Changed to a better board for better overclocking potential. Also, Ryzen needs faster RAM for optimal performance. Price remains similar.

PCPartPicker part list / Price breakdown by merchant

CPU: AMD - Ryzen 5 1600 3.2GHz 6-Core Processor ($197.88 @ OutletPC)
CPU Cooler: Deepcool - Maelstrom 120T 83.6 CFM Liquid CPU Cooler
Motherboard: MSI - B350 GAMING PRO CARBON ATX AM4 Motherboard ($91.98 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3000 Memory ($184.99 @ Newegg)
Storage: Samsung - 850 EVO-Series 500GB 2.5" Solid State Drive ($139.99 @ B&H)
Storage: Seagate - Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($59.99 @ Amazon)
Video Card: EVGA - GeForce GTX 1080 8GB FTW DT GAMING Video Card ($568.89 @ B&H)
Case: Phanteks - Eclipse P300 Tempered Glass ATX Mid Tower Case ($63.98 @ Newegg)
Power Supply: Cooler Master - MasterWatt Lite 230V 700W 80+ Certified ATX Power Supply
Case Fan: Corsair - CO-9050015-BLED 52.2 CFM 120mm Fan ($11.08 @ OutletPC)
Case Fan: Corsair - CO-9050015-BLED 52.2 CFM 120mm Fan ($11.08 @ OutletPC)
Total: $1329.86
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-12-18 14:37 EST-0500

The cooler is decent but not the best of performer. You can get some clocks beyond the stock though...
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/68060-deepcool-maelstrom-120-water-cooler-review-5.html
https://www.techpowerup.com/reviews/Deepcool/Maelstrom_120/9.html
If you dont own it already, it is not recommended.

 

[brominecraf]

What cooler would you recommend instead? Or is an aftermarket cooler really necessary?

 

[Hellfire13]

The stock cooler can get you upto 3.7-3.8ghz or thereabout. It is plenty. If you wanna hit 4ghz you need top of the line AIO. But the price you pay for those .3ghz is not really worth it, unless you are an enthusiast.