15% attackpower is good, not good enough to compete with Seraphim or Final Verdict though.
throw in the 10% haste and Empowered Seals is about equal to Seraphim and Final verdict.
..... except it drags a full Templar's Verdict (or Final Verdict) every ~18 seconds and completely messes up your rotation if you get procs and such you want to use asap, simple fact of the matter is that EmpS drags way too many GCDs for us to use- same problem as Protection has with it. Yes it's great (the buffs) but the actual way to get them needs to change, cutting the GCD triggered by swapping seals is one of the suggestions I've made- pulling them off the GCD would remove any play from the talent and might as well be turned into a passive.