Go Hard - I've found that I did have to pause and every now and then, but not frequently. I mainly used pause to reposition my companions either to avoid danger or to get to a better vantage point.
Templar - I don't think you'll be able to unlock this right away, but from what I can tell you...warriors are awesome. I don't play one, but I use Cassandra as my tank and I swear, without her abilities I don't know where I'd be. Warriors have some incredibly useful skills.
Map Size - There are different maps. Individually, I don't think they're bigger than Skyrim's as a whole, but I highly doubt that will be an issue. Also, I've only played the first open map (Hinterlands) so I could actually be wrong about the others. Regardless, there's plenty to do and find on just one map alone, so you won't be disappointed.. Now, compared to Mordor, it's huge (even just one map). In fact, I don't think Mordor even holds a candle to Inquisition's maps (in my opinion). 