Here are the cons
1) Nyboma may have been used too much
Nyboma may have been on too many Madilu songs. It looks to me at times, it looked like Nyboma may have been exhausted on being on so many Madilu's songs. Just listen to Bonne Humeur, you can see a little bit that Nyboma may have been exhausted. This was sort of confirmed on a Nyboma interview, where it sounded to me like he was kind of tired always having to help Madilu out on promotion of this album when he spoke about this project.
Even better, listen to Pouvoir, Nyboma actually sang less than he did on L'Eau or even Album 95.
2) One Sided Affair
This leads to me being this part. Madilu always wanted Nyboma in his works but it did not seem mutual. On Nyboma's work, he hardly invited Madilu on those works (only 2006 album of Kekele would Madilu appear on a Nyboma work). Good example would be on Nyboma's very successful album Anicet which was done in 1994 which was the same time that Madilu did Sans Commentaire. It was clear to me, Nyboma was not a big fan of Madilu as Madilu was of his.
3) Missed potential guests
With Nyboma and Madilu going well, Madilu forgot that there could have been guests that could have completed Madilu's great solo work. The only time that was not the case was on Album 95 or Pouvoir. Album 95, he worked with Dindo Yogo and they had a harmonious sound on Pardon. On pouvoir, he had a great singing moment with Desouza Santu who sang with Pepe Kalle. But other than that, other albums did not quite have someone great that could have matched Madilu's crazy voice. But there were moments where some songs should have had Nyboma's voice but did not espcially on choirs.
4) Lack of duets
Madilu and Nyboma did not do enough duets. That makes me mad since they were a nice duo. They actually had a great sound together and there are moments where it should have been them and no anyone else. I'll give an example. Aminata and Mon Case of Bonne Humeur (Dernier Volonte). Those songs could have made a great duet but instead they have choirs of others which stinks because you could have a harmonious moment between these two men. Final one could have been Wawali Mobunda. That song should have been a duet between these two. Even on their signature album Voisin, they did not do duets. It is so absurd. They probably never realize how perfect that they could have been together as a duo. But then again, they also could added a third person
5) Missed a third man alongside them
Nyboma and Madilu missed a chance to find a third man that could have been perfect with them together. I mean they failed to find that place. It could have been (and should have been) Wuta Mayi. But unfortunately Wuta Mayi was used with Nyboma with someone else. Or it could have been Dindo Yogo. I mean Dindo Yogo loves singing the countertenor role while Nyboma could have done the the tenor with Madilu's unpredictable baritone. Or it could have been Luciana himself.
Or even more shocking it could have been with Pepe Kalle. I mean Madilu often said that he was his "friend". So if Pepe Kalle was such a great friend, Nyboma and Madilu should have gotten him to make a trioship for a project where they could have sang together during Madilu's earlier days as a solo singer.