Rystet you don't know how right you are, but I am sure he dose lol.
Attacks are done on a two roll system. First roll determines a hit or miss (miss, dodge and parry/deflect AKA Defense).
Second roll determines a shield, critical hit or normal hit. The second roll is % based, with shield and crit adding together, and anything left out of 100% being normal hits. Crits always take precedence over shield, and shields over hits, so a high enough crit chance can push shields off the table.
Shield Rating, and Absorption are not going to be as important and beneficial as pure defense, but its still a useful stat, and this talent should be taken.
The Problem with the Shield mechanic, is that you have a good chance to shield the attack, but shielding the attack only reduces the damage done by a percentage. The percentage its reduced is dependent on a secondary stat... Shield Absorption. So, you need to worry about 2 stats just to partially reduce damage taken. Where as with defense its a flat percentage and if it activates you completely avoid all incoming damage.
This does not mean that Shield Rating and Absorption stats are bad, they will just not take priority over Defense. As time goes on we may find situations where a Shield focused set of gear actually has advantages. In that case we could have 2 sets depending on the situation.