Were the changes that were done to not get too close to GW's IP done as a preemptive precaution, or did GW actually press them about it?
Pre-emptive. GW never took notice of T9A thus far.
For GW to go after 9th Age would be stupid. T9A isn't competing with anything GW actually tries to sell. On the contrary, a thriving T9A would be a boon to the sale of GW fantasy miniatures, since GW is, effectively, the primary miniatures manufacturer for T9A. Heck, that'd fit neatly with their new self-identification as a miniatures (rather than a gaming) company. That's how historical wargaming has worked since forever - different companies make rules and figs, there's healthy and completely separated competition in both, and everyone gets to do what they do best.
Considering what GW has become though, the fact that such a thing would both be an utter dick move and commercially pants on head retarded doesn't give any cause to believe it won't happen. Quite the contrary.
Yes and yes, I believe that's what mostly everybody thinks.
-Z
Just to kind of echo what you said:
Yes, GW has had a shift in their thinking and business practice. How long term this goes has yet to be seen though.
When AoS was released, GW really pressed home that they were not about tourney level air-tight rules, points, etc... Even to the point of some GW stores allowing T9A to be played in store.
....and then sales tanked.
Many reasons for sales tanking though. At first they thought it was because of the no-points. So they released the generals handbook and that sold well. But then sales still tanked.
It was not until they released the start collecting boxes at the very reasonable price point that they had a turn around. Honestly it was just that they overpriced their product.
So in the future, if GW feels that points and rules are a big factor in sales they would happily come down on any 3rd party rules set. T9A simply can't afford to defend a lawsuit because they are non-profit. So they had to move away.