While the "flow" of a service certainly cannot produce worship in any of its above-mentioned dimensions (only the Holy Spirit can do that), the lack of flow in a service can certainly interfere with true worship. Flow in a service simply mean that the mechanics of the service don't draw attention to themselves, and thus distract from a proper focus on God Himself.
A worship service of course consists of a variety of elements and parts; the trick is to avoid an awkward sense of repeated starts and stops. To draw an analogy: the cars of a train may have different functions-- engine, box car, tanker, caboose-- but all are linked together and are heading in the same direction. So also should the various elements of a service have a feel of connectedness; our goal should be to minimize unnecessary distractions so that our focus can be on God-- the One we have come to worship.
Avoiding Impediments to Service Flow
Lack of Continuity
It is admittedly difficult to link service elements in a convincing way if there is no common content or thematic links between them. Songs, readings, and other elements which bounce from one theme or attribute of God to another may indeed have God as common focus; but beyond that, little continuity is given to help the worshiper focus, reflect, and respond on a specific aspect of God's character.
Many liturgical traditions have something of a built-in flow, but even some of these do not escape giving the impression of a lot of different things simply strung together, arranged sequentially with little connection between them. Free church worship often errs even more in this direction: since there is not as tight a traditional structure into which the service elements fit, those elements can seem even more disjointed and unrelated.
However, there is the opportunity, in both liturgical and free church forms, to construct thematic services, where a theme (e.g., the love of God; Christ the King; etc.) is carefully woven through the parts of a service, and the music, readings, and other elements are all chosen to reflect that theme. This gives an organic unity to a service and thus enhances the sense of logical flow.