<Updateed 3:15 Eastern Time>

Store is back up, I just bought the expansion via TP and it worked fine.  Although I did have to re-log to get the Rohan Awaits Quest to show up.

<Update>

<Update ~1pmEastern> A couple other issues outside of this list:

<Update>

Nice and early, the known issues for Rohan have been posted.

Many little cosmetic and screwy things like:

When using the Mounted Strike skill on enemies to the left, the player character animates as if attacking to the right.

But this one might be VERY critical for many folks:

Rohan – Rohan Awaits – If you’ve already completed the Langhold quest line, there’s no way to complete ‘Rohan Awaits’. Completing Rohan awaits before completing the Langhold quest line will prevent this from happening.

It might not be a bad idea to keep an eye on that thread for new things that pop up during the day.