Yeah but a flare providing reconnaissance during broad daylight makes plenty of sense... Forget the time of day it's a fucking flare. How does it
Flares are literally used in real life modern combat to highlight enemy positions. There are infantry fired flares, which work a bit like a firework and quickly light up an area making enemy movement really obvious, if you see one going up your supposed to freeze and slowly lower yourself to the ground, to avoid sudden movements which will be easily spotted.
Second is flares fired by artillery, which are slower and fall on a parachute, when you spot these you are supposed to dive to the ground as fast as you can.
It doesn't need to be dark at all. They do their job in anything but the brightest conditions.
Back to topic: recon flares is literally one of Spec Ops trade mark and best abilities, it needs to be strong. Even if it's made to be more obvious, say with an audio que.
Other commanders with recon have it as a secondary ability usually with powerful off map strikes. This is part of the balance.
Also Soviets have amazing anti air cover in their AA half-track, which is cheap and has good utility as a light vehicle in mid game before becoming a support unit for its AA.
So any axis abilities with planes are supper meh when playing soviets.