Not owning the marks to a project and more specifically not having the agreement with the owner of the marks to use the marks in a commercial capacity... does limit a sponsoring entities options in terms of revenue generation that can be used in the future. It's not impossible, but I would argue that its limiting..especially if the marks create an unfair playing field situation for potentially competing commercial entities. If the marks were transferred into the care of a non-profit which had the authority to license commercial use in a rand licensing capacity that would be better as it would allow multiple commercial entities without a conflict of interest.
But lets put this in the context of what has actually happened over the last couple of months. When Canonical was the driving commercial entity supporting Kubuntu, their stewardship of the marks seemed reasonably equitable to me. But that relationship has changed. Canonical has acknowledged that they are taking a step back from their role. Which is fine, I think they've spread their meager resources way to thin for too long and they've finally retrenched into a more focused engineering effort around Unity. Again all of that is perfectly fine.
But if they aren't going to be the driver for Kubuntu, and they aren't looking at Kubuntu as a revenue stream as part of their support offerings (And remember 12.04 LTS Kubuntu is _not_ going to have commercial support offerings from Canonical..this has been restated by multiple Canonical execs. Its a bit confusing but there it is) then holding on to the marks and limiting how other potential commercial entities can make use of the marks to build a business that pays for Kubuntu development is _not_ in the best interest of the Kubuntu developer nor user community.
The commercial entities which are stepping up to _fund_ development need to be able to use the project brand in a commercial manner without interference or paying tribute to another commercial entity that has stepped away from its obligation as chief commercial supporter and is now squatting on the brand value..brand value built primarily by unpaid volunteers.