in Ur image posted i notice that ip route had no distance 1 you have distance 2 and 3 . try to make it 1 and 2.
i don't think it will make big different, but try it
as we can see that in Ur interface list isp2 has some traffic.
be care full for ur firewall mangle i can see that in mark connection something not right sine there is in connection mark (no-mark)
add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses:2/0 \
action=mark-connection new-connection-mark=
wlan1_conn passthrough=yes
add chain=prerouting dst-address-type=!local in-interface=Local per-connection-classifier=both-addresses:2/1 \
action=mark-connection new-connection-mark=
wlan2_conn passthrough=yes
and mark routing you has tow route ips2 it showd one isp1 and isp2
add chain=prerouting connection-mark=wlan
1_conn in-interface=Local action=mark-routing new-routing-mark=to_wlan
1
add chain=prerouting connection-mark=wlan
2_conn in-interface=Local action=mark-routing new-routing-mark=to_wlan
2
and what u mean by large traffic ( many connection. or large file download)
pcc load balance has pcc
(peer connection classifier ) and that new option
it better to export your mt fire wall and post it