Again, problems with different schools. Switching from a defensive stance to an offensive stance can prove difficult to some schools, especially when attacks must be healed off. Because shrike users can do damage much faster than a player without shrike, trying to be aggressive against them often ends in defeat. Even without shrike, with the massive amounts of damage often seen in the arena, defensive schools have lost much of their usefulness. Storm shields are not unfair, as often even with storm shields storm can hit massive amounts of damage, they can be easily removed for low amounts of pips, and without storm shields, the other schools would have no good way to counter storm, while storm could counter large amounts of resist with pierce and converts. An example of how shrike is overpowered happened to me yesterday, when I tried a practice 4v4 match. My team was second to a team with a storm in last position. First round, the storm bladed. Second round, infallible. Third round, they stunned us and the storm used shrike. Fourth round, with 70% shields on two of us and a stun shield on our life, the storm did an 8,000 damage storm lord through the shields (And around 60 resist on the life). Without a death spamming virulent plagues, there is no real way to counter this, and even with a death spamming them, the opponents used death dispels on our death. I personally do not find this fair in any way, but I guess that's just me. If the PvP community wants 4 round matches where the most damaging schools dominate, I can't really stop that.
The difficulty of switching stances used to be the case before Aquilla/Khyrsalis. However with the release of these worlds any school can effectively switch to the offensive. It is possible for any school to get 80+% damage boost, it is possible for any school to get 600+ critical rating and it is possible for any school to gain 15%+ pierce. I agree perfectly with you that storm shields are perfectly fine much as I see shrike as perfectly fine. Both of them are a)Temporary, b)Have their own drawbacks, c)Can be countered. I do agree that in team the aggressive schools have quite an advantage but that problem reflects the single issue that has plagued team matches from day 1, the turn system. The strategy you stated would not have been effective with one wizard or a different round system as that match required several different wizards casting 4 of their own spells before the other side even had a chance to react.