No - more than likely (like 99.9% of the time), it would not be slow because the publisher has not finished. For most environments, the CAD worker that is executing the publish is up on the server, while the user's CAD is processing on that user's local machine's hardware. The only way I could really see it being affected is if they were both running on the same hardware, which is definitely not recommended anyway.
It sounds to me more like it is just a really large model... which certainly happens. Do you know how large the model is in RAM when it is fully loaded? That could be one reason why the model can be "slow".
There are things you can do to accelerate the publish times for a server (such as considering publishing as a "Positioning Assembly"), but there are pros and cons of doing that. Similarly, there are things you can do locally (config.pro settings, simplified reps, as well as modeling practices) that can improve working with the model locally as well.
Thanks,
James Sullivan
