I remember why I didn't look at the Templar anymore. The Angus seemed to be more suited to play around all mountain. Specs said full twin and all mountain freestyle, in stead of all mountain and directional shape, but maybe there is not so much difference.
You are correct - Angus is a true twin (but with an offset) while Templar, Taipan and One are all directional twins.
I've been riding mostly on a true twin board last year and to be honest, I largely stayed in my "native" regular position, rarely goofy. For occasional switch a directional twin is not that bad anyhow as it is shaped the same way on both ends, just with a different flex. And you should be able to centre the bindings still, most of these boards have a slight offset only.
So, bottom line, if riding switch is very important to you and you see yourself splitting time 50/50 between regular and goofy then yes it makes sense to get Angus. On the other hand if you only switch ride occasionally then a directional twin will be better.
Furthermore, Rossignol's website recommends Taipan through beginners to advanced, Templar - intermediate to advanced; Angus and One both for advanced to expert. All boards are in the all-mountain classification.
Overall, I am impressed by the price points Rossignol offers. Comparable boards from Ride, K2, Burton, etc., are much much more expensive. Never really paid attention to Rossi before...