It will be super cool if ip/netmask functionality will be addressed by wgconf
Currently we testing this systemd units for wireguard ppa:
: wireguard.service
# This service is actually a systemd target,
# but we are using a service since targets cannot be reloaded.

[Unit]
Description=WireGuard service
After=network.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true
ExecReload=/bin/true

[Install]
WantedBy=multi-user.target

:wireguard@.service
[Unit]
Description=WireGuard connection to %i
PartOf=wireguard.service
ReloadPropagatedFrom=wireguard.service
Before=systemd-user-sessions.service

[Service]
Type=oneshot
EnvironmentFile=-/etc/default/wireguard

# %i is your connection name created from .conf files in /etc/wireguard
# For ex.: Use systemctl enable wireguard@server.service to enable server example setup
# You can store unlimited amount of various connections in /etc/wireguard

ExecStart=/bin/ip link add dev wg%i type wireguard
ExecStartPre=/bin/sh -c "/bin/systemctl set-environment ip=$(/usr/bin/head -1 /etc/wireguard/%i.conf | awk '{print $2}')"
ExecStart=/bin/ip address add ${ip} dev wg%i
ExecStart=/usr/bin/wg setconf wg%i /etc/wireguard/%i.conf
ExecStart=/bin/ip link set up dev wg%i

# We can't predict routing in your environment, but we can make it easier to setup in /etc/default/wireguard
#ExecStart=/bin/ip route add $0_1 dev wg%i
#ExecStart=/bin/ip route add $128_1 dev wg%i
#ExecStart=/bin/ip add $demo via $common_router dev eth0
#ExecStart=/bin/ip route add 
#ExecStart=/bin/ip route add 
#ExecStart=/bin/ip route add 
#ExecStart=/bin/ip route add 

ExecReload=/bin/ip link del dev wg%i

[Install]
WantedBy=multi-user.target
:/etc/default/wireguard
# Common values could help you setup routing faster
# You can set routing rules in /lib/systemd/wireguard@.service file

0_1="0.0.0.0/1"
128_1="128.0.0.0/1"
# demo.wireguard.io
demo="163.172.161.0/32"
common_router="192.168.1.1"

And test files:
: server.conf
# 192.168.177.1/24
# Since you need to set ip address manually with ip or ifconfig we use workaround and read ip/netmask from first line of every config file
[Interface]
    # You can generate own public and private keys with: wg genkey | tee privatekey | wg pubkey > publickey
    # Its strongly recomended for you to generate own keys!
    PrivateKey = qFstR3l2HG5WQJ0qoQG0G87c039kXR5zN7vV+bUKb0Q=
    ListenPort = 41414

[Peer]
    PublicKey = 40UuwEq4H1gaY1rpmwuW0hUyOnGvXuoQIMctOyOrEAs=
    # Outside world access blocked in example setup
    AllowedIPs = 127.0.0.1/32
    #AllowedIPs = 0.0.0.0/0
:client.conf
# 192.168.4.5/24
# Since you need to set ip address manually with ip or ifconfig we use workaround and read ip/netmask from first line of every config file
[Interface]
    # You can generate own public and private keys with: wg genkey | tee privatekey | wg pubkey > publickey
    PrivateKey = WEAuaVuhdyscyTCXVfBDJR6nf9zxD75jmJzrfhkyE3Y=

[Peer]
    PublicKey = Uha1fHzOY6hPhq54fcrElVdNF/XQDzQ90rDT7+IqIgA=
    Endpoint = demo.wireguard.io:12912
    AllowedIPs = 0.0.0.0/0
    PersistentKeepalive = 25

After some talking with ">Egbert, I think to move routing to separate unit, but still read routing configuration from conf files. I just like ovpn way, when for user is just enough to copy single configuration file.
If ip/netmask and routing will be done with wgconf, and will be located inside single config file, this will be huge success for all users.