Steelwing Dragonite
What do you use them for? For me it´s pretty clear that for offense DB and DT are the better choices. DB is faster, builds more energy and does more damage, so there is no debating here. If you compare DT to SW, SW is actually faster (but less energy and damage), but if you value quickness for better dodging then DB is still your choice.
On defense we already have the gamepress rankings and it seems DT is superior no matter which charge move you get. In the past I maxed out every Dragonite I got because SW was for defense and DB for offense, but now it seems that SW is ok for defense because of it´s type coverage but DT is always the superior choice. I have two SW Dragonites already maxed out and they are good for positioning in gyms at 3100 CP, but I wonder if it´s worth it to invest dust and candy anymore if my next Dragonite gets SW again? I have two DB Dragonites, so there is really no urgency, but it´s sad that the movesets were changed in a way that some moves are simply inferior in every way for a rare pokemon which every player is aiming for. I think it was good before that if you got to finally evolve a Dragnonite you knew no matter what that you could use him either for offense or defense, but now it seems that thre will be a lot of dissapointed players if they get SW on their first Dragonite.
Answers
Incorrect, Dragon Tail charges energy faster than Dragon Breath and also does more damage while doing it. Only thing in DB's favour is dodging (which is actually a big factor though)
Steel Wing/Dragon Claw is now the best legacy defensive moveset, and is on Par with DT/Outrage (those dragon claws really mess up the dodging patterns and one will connect eventually).
But yes, new Steel wing variants with HB/Hurricane and Outrage are kinda...meh
On offense:
Dragon breath>Steel wing>Dragon tail - idc about more dmg and energy, dragon tail is awkward as fuck. Best currently available offensive moveset is steel wing/outrage imo.
On defense:
Dragon tail>Steel wing>dragon breath. No explaination needed.
Edit: this i based on personal experience - I have a dragonite w every offensive moveset (DT/OR, DB/DC and SW/OR)
Well, as i said; it depends on your style - if you only dodge charge attacks, DT may be your best option. If not, SW is superior imo. Every Spreadsheet is going to defy this logic, because dodging won't be taken into account, although i am eager to see the Gym Attackers tier list.
Dragon breath will always be the best imo, but since this is not available anymore, SW comes on top. SW does 19ish dps (0,8 sec cooldown) while DB does 20 (0,5 sec cooldown). The difference is really not as big as you would think. Even a SW/HB (worst charge attack) is serviceable on offence now.
I don't get the DT hate... I prefer it to DB. It deals huge damage and allows charges your other move quite fast. SW is my least favorite Dragonite quick move.
FWIW: Regarding DT/DB, I typically only dodge charge moves which might explain why DT is superior for me. I have a PoGo+ so potions aren't a problem and I find that cruising through the gyms and needing to grab a few more potions afterwards is a more satisfying option than dodging every move.
DT is the best moveset in DPS/EPS terms of all quickmoves.
However, if you value doding enemy quick moves, then the faster Dragonbreath and Steelwing might be better than DT for you.
In that scenerio for Attack DB > SW > DT
Funny story though, a week or so ago I asked for a vote between a Level 22 Dratini with 12 def and a Level 17 Dratini with 13 def (both had 15 attack/hp) most chose the Level 17 which is same as I evolved. But I also got a Level 29 Dratini with 15 Att 14 hp 7 def before my Sunday egg came up. I got steel wing hyperbeam. Boo, I won't invest in that. I do wish I had done the level 29 one, because even with no investment, I could toss it in Gyms.
I've said this a few times already here, but Gen2 was a big NERF to Dragonite. Fewer great movesets, and Steel Wing is basically obsolete now. The only SW moveset I would want is SW + Outrage, and that's just because Outrage is so strong and Steel Wing gives decent type coverage despite being inferior DPS and Energy.
Offensively, Dragon Tail is a bit clunky but in most scenarios you can fit 2x DT in between enemy quick moves, and still dodge pretty effectively. It's definitely not on the level of Dragon Breath in terms of overall effectiveness, it blows Steel Wing out of the water. I'd rather do insane damage (and gain energy faster) and miss a dodge on a quick move here and there than be gimped by using Steel Wing.
DB-DC is still the king sweeper. DT-OR is pretty close, just a bit more difficult to use.