The general view is that uniform well-knit canola crops are the best for straight combining, but it can be argued that leaving thin multi-stage canola may also be lower risk than swathing.
Short or thin crops will not produce a windrow that rolls nicely, and may not have the stubble to hold that windrow and prevent it from blowing. Straight combining eliminates the risk of swaths blowing.
Leaving an uneven crop standing for straight combining may allow more of the later pods to mature and contribute to yield. Before leaving the crop, assess how much of the yield potential is tied up in these later pods.
Desiccation may be required to dry down weeds and very late canola plants to facilitate straight combining. Hold off on desiccation as long as possible to let as much of the crop mature, then go in with desiccant a few days before harvest.