For pure ST dps ele dev should beat out a resto talent build on really short fights.
Elemental Devastation on an otherwise conventional Enhancement Shaman is worth about half the value of Thundering Strikes due to low spell critical and only being able to use two Shocks per 10 sec window.
About the only time Elemental Devastation becomes (somewhat) worthwhile is on a pure Spellhancement build where you’re going all the way to Elemental Fury and using primarily spellpower/spell critical gearing combined with high speed melee-focused weapons (normally daggers). Completely analyzing this choice is well beyond what I could present here, but in general it will provide less single target damage.
The value in such an approach is that (a) you do significantly better AE damage and (b) your heals are significantly larger.