Too much/ overly aggressive agitation leads to the developer flowing in a stereotypical way through the sprocket holes leading to streaky negs, but of course YMMV.
Bromide drag is an entirely different, chemical-based issue and is ameliorated by gentle but regular inversions.
Pre-soaking is an important step in balancing film and developer temperature. It also assists in developer take up in areas where less than ideal water quality can affect this. Again, YMMV. If it's not necessary for you, then don't do it. No need to overcomplicate matters. The OP is having problems, so I am making suggestions on issues that may and could cause the reported issues. It seems you are not experiencing these issues, so more power to you. It's frustrating when it doesn't work out, and when we get it right, it is easy to forget that.
Final point - just because Ilford does not mention pre-soak, it doesn't mean it is not helpful. Ilford used to suggest drying films with a hair drier ... imagine that - a fan-powered dust distributor firing it onto overly heated sticky gelatine. Disaster.