What reasons to avoid change do you hear most often when trying to implement new data initiatives, and how do you get these challengers on board?

Oh what a question! I am sure there are many perspectives and differences between organisations. I would word this as not avoiding 'change' but avoiding 'fixing the foundation'.

With a strong foundation, good meta data and master data management you can build and deliver new data assets/initiatives with 'relative' ease (which doesn't mean they will always be a success or 'stick') - and at some point, your organisation has to grasp the nettle and 'fix the foundation' and for this alone no-one (usually) is recognised as a hero. 

In my experience the resistance to new data products is linked to trust in the data itself. 

Another scenario is where I see individual leaders attach themselves personally to a technical solution - often out of a detailed lack of knowledge/understanding - and this then becomes a roadblock to change. I'd be interested to read more comments in this thread if others have examples. Great question.

The biggest complaint usually is how much extra work this will be for the team. To work with the team, I like to start with a crawl, walk, run approach. Let's start doing this and see what feedback there is from the team to make it better to get to the walk stage and repeat.

Alignment across functional and business group is one of the important steps