I'd say Glass Cannon doesn't really fit in with "nothing that will make the game too easy". One thing that could cause problems is putting points into non-essential attributes, or doubling up skills that aren't useful to double up on (e.g. crafting, blacksmithing, bartering).
Speed gives extra recovery AP at odd numerical values, so 7 speed, 5 con could be considered better to start. Don't forget the perception though, you'll have trouble hitting non-stunlocked enemies at any range without any perception. Also, especially for your first playthrough, you may want a character with high perception (and possibly the light stepper talent) to reveal hidden secrets.
It's perfectly possible to build functional and fun characters without giving them all skills that are considered generally useful like Tactical Retreat.
Also, what Hiver said.
And have fun!
