Yep - not only is there no catch right now, but they literally can never add one. The SRD is released under CC-BY-4.0.
The only point of contention is what happens to their new product, One D&D, which will probably retain some nasty payment structure, and almost certainly not be OGL'd. That's fine though - if they build a walled garden around One D&D, they simply won't be able to compete against the open community of 5e.
> not only is there no catch right now, but they literally can never add one. The SRD is released under CC-BY-4.0.
They can't change that particular SRD, but material not in the SRD can be changed as can new material. Also, as they leave the old OGL intact, it is a catch in itself: 1) It's generally restricts rights much more than grants them [0], and 2) WotC believes they can revoke it at any time.
Yep, everything not CC is still under the sword of Damocles. The good news is that the vast majority of players and third-party publishers are using 5e, so this announcement protects them forever. It would not be unexpected for them to use this as a way to dwindle support for OGL1.0a, but either way the state of affairs today is far, far better than a few days ago.
