If SquareEnix insists on keeping the current 3/3 spike formula for a theoritical tier 2 spikes(as opposed to the suggested 6 all elemental damage spikes), then a reworking of the mechanics behind these particular spells might be in order.
I proposed this under the "blink2" thread, but basically not only increase each effect by a factor of X, but having a "regenerative/potency" effect on each.
For example..
Blink2, would gain an additional 2 shadows(random hit), but would be capable of regenerating all lost shadow while duration is in effect(if not attacked)
Stoneskin2 increased damage cap with same "regenerative effect" as blink.
Aquaviel2, who knows how this works, but same premise.
All (3)types of these "spikes" would raise initial casting/recasting times and have a normal stoneskin durations of 5min. Same composure rules apply(triple timer).
As for the damage spikes(blaze, shock, and ice), there individual potencies would increase as a redmage continues receiving damage to a cap of X/hit. Whatever, the actual damage is...let say additional of 20, then the new cap could be raised from 20,21,22,23 all the way to say 50. Which means combines both enspell2 and spikes2 would have redmages doing about an additional 100points of damage based solely on being attacked and damaged.
While these 2 suggestions sounds overpowered, let's really look at the numbers. I'm not including Utsemi in the discussion since that particular spell is already pushing RDM over the limits as long as a player goes RDM/nin. Most mobs at our "level" or above can pretty much shred any Mage hitting for 200 or more damage, or multi striking. Both the blink and stoneskin suggestions really only offer a partial advantage over time, much as regen can't save a tank from dying only in recovering. The regenerative effect doesn't have to necessarily be strong(think 1 shadow/3~7 tics or 1pt/1tic stoneskin...debatable).
The spikes, only contribute as long as a RDM has the hate from a party which is practically never, so this would only help in soloing and limited kiting/holding mobs.