Since I did a Post for the Me 410 B-1, I thought it only fair I did one for the IL-10 aswell
The IL 10 was never that exciting in BR 5 and suffered the same underwhelming payload as the Me 410 B-1. It too has been collecting dust for a long time and has become obsolete (even more so) with new tech tree additions and finally Jets. In its current state, it’s probably not even that interesting for BR 3 (however it would give soviets a 250kg bomb attacker that they do not have)
USSR does not need another IL 2 Option in BR 3 so Buff is preferable.
There are two options I will suggest for this plane:
Option 1: (This one Should be Priority!)
BR 4 
IL-10
- Move to BR 4
- increase payload to 2x 250kg bombs and 4xRBS-142 Rockets (or M13-uk Rockets)
This Would be the preferred choice as it becomes slightly more appealing at BR 4 with rockets in addition to the bombs.
Option 2:
(USSR does not need another IL series in BR 3…but without a buff, it may Aswell be at BR 3 where it might see some use)
BR 3 IL-10
- Move to BR 3
This Option offers a slightly different configuration to what Is already offered at BR 3. It carry’s a standard payload for most BR 2/3 attackers. Even Some fighters at BR 2/3 carry this payload while being faster and more maneuverable.
Speed Comparisons:
The IL 10 is quite a bit faster than the IL-2s at BR 3 (But a less effective loadout). It is still a fair bit slower than most BR 3 attackers.
Conclusion:
The IL 10 has been superseded and collecting Dust at BR 5 for a while now. There is nothing remarkable about it no reason to pick it at BR 5 at all.
Option 1 is the desired outcome, but in the meantime Option 2 can be achieved quickly until more time can be spent on it.