Post by GenXCub
A few things to mention...
The amount of hit rating to get 1% spell hit is not the same as the amount of hit rating to get 1% of melee hit. Yes, +1 hit rating applies to both, but both have different Rating:1% ratios.
32.79 (melee) vs 26.23 (spells) to get 1% of hit, respectively.
When soft caps and hard caps are mentioned, you usually need more information. Passing a soft cap means that any more of that stat (hit in this case) becomes less valuable per point, because one or more abilities that it affects is no longer improved.
8% melee hit (which DWS helps) is the soft cap for special attacks (Stormstrike, lava lash, Windfury).
Any melee hit above this ONLY helps white hits.
17% spell hit (which DWS does not help) is the Hard Cap for spells vs. Raid Bosses.
Let's assume that you have a moonkin or shadow priest in the raid (and no draenei). This means you just need 14% spell hit, or 367 hit rating. This only comes to 11.2% melee hit rating.
To fully cap melee hit (white damage) vs. Raid bosses, you need 27% total melee hit (which DWS does help).
So can you do without DWS, once you're above one or more soft caps? Yes. But it doesn't become totally useless unless you're at 27% melee hit cap, and that's not something that people care to reach. What other talent do you think is worth it?
17% spell hit is usually mentioned as THE hit cap, because after 8% and before 17%, hit rating helps melee white damage AND spells. After 17%, it only affects melee white damage, and at that point, crit, ap, haste, agility are worth more per point, where they weren't prior to the soft cap.
What this all comes down to is this:
Let's assume that you have 367 hit rating to cap your spells when there's a shadow priest or moonkin around. This puts you at 11.2% melee +hit. DWS at this point increases your white damage by about 2% per talent point.
http://www.wowhead.com/?talent#hVbhVZhbxIoxdIhzsRuVoThere's the build without DWS and 4 talent points remaining.
Reverberation is out. The way things work at level 80 on enhancement, you'll never need the extra second on shocks. You're already using up all your global cooldowns on lava lash, maelstrom weapon, stormstrike, and refreshing your lightning shield.
Earthen Power, Frozen Power, Improved Ghost Wolf, Earth's Grasp, Anticipation, Toughness are, for the most part, PvP talents. So where would these points go? Maybe Elemental warding if you favor that over hit, but most DPS classes focus on DPS talents, not survivability talents. Finishing Ancestral Knowledge is kind of a waste, as you'd get about 10 attack power per talent point... another waste. DWS is almost the only place a PvE shaman has for the extra points.