Is any tactic useful for these mad corsairs?
Or they are really useless?

Their special rule seems very odd...
they need to stay near to a Bo'sun for not going crazy and charge friendly models, but they are effective only when they go crazy and obtain +1 to wound

What do you think?

I think that the reavers do have some tactical use. The controlling player can use the Bo'sun to control a fair number of them until they are enemy models in range of enemy models to take charging priority. Then the Bo'sun can be moved back to set the reavers loose. This will mean looking the banner effect, I suppose, but I think it would be doable. I think the general purpose of the rule is to make the reavers a useful tool for a player to mix into his army rather than the objectively better version of the corsair that they used to be. I just wounder if they will be better than bringing more crossbows who can punch armor just as well without the negative side effects. Plus, their low defense means they are going to be easy pickings for the elves, Dale, and Uruk-hai scouts.

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"Draw your sword with a heavy heart, but swing it with a heavy hand"

I think they are still beasts, but needs playtesting to see if they worth it indeed. Converting them with axes is one of the few cost efficient conversions (they will cost +1pt). The reason is that they already have low defence and the "to wound" roll can't be lowered more than 3. If they win, they kill, so they are perfect to grab objectives. The way of using them to do so, is well described by Wan. I will ally them with a serpent horde force with 50% shooting. They provide a strong strategic element (in new meta I think it is good to have a section that can hit hard) and if you position them and your archery in an efficient way, I think they are gonna have success.

No more the shadow lord combo. No more combos with spearblocks and F5 with piercing and staff. But still a good choice to consider. Indeed elves counter them...

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