The backlog problem is always going to be a problem until the backlog is dealt with.
Unfortunately, I cannot answer how long that will take. I think IRCC would be better suited to answer that question.
I would not say that the influx of Haitian migrants specifically would pose a concern to the backlog. The reality is that as long as socio-political conditions in countries of origin continue to worsen and go down the path they are going down, people will continue to seek refuge.