Many other users have already pointed out some great points but yeah I can see some stuff you should try out. Firstly I always suggest running Shed Shell > Leftovers on Ninetales.
Losing the weather war on a sun team is worse than for any other weather team and Leftovers recovery isn't as good on Ninetales as being able to evade Dugtrio and the rare Move trappers. If Dugtrio is Banded you effectively get a free turn as well so its definitely worth trying out . Another thing I noticed was that countering other other sun teams and most of your threats can be done by giving Dragonite a Choice Band
. I know your saying LOL Dragonite take on Mamoswine what you on, but but believe me when I say that Band gives Dragonite a ridiculously powerful Outrage and Fire Punch and ExtremeSpeed is a priority move that beats all other priority users with its +2 priority ! The reason why you shouldn't use DD nite is that imo it is far too easy to take down in BW2 with the abundance of Mamoswine and other Ice type move carriers with the introduction of the theirans, and 2 set up sweepers that are weak to Ice can mean some sweeps will be ending prematurely. A Dragonite set of Superpower/ ExtremeSpeed/ Fire Punch/ Outrage with 8HP/ 248Atk/ 252Spd/ and Adamant will be real good for your team. Also Mamoswine will lose a chunk of health from ExtremeSpeed anyway so Mamoswine won't be getting off for free either. If you decide DDnite is better you should try out Superpower > Earthquake
so pesky balloon tran don't annoy your team and although you will lose a boost, Lilligant has 1 less enemy to worry about before it starts sweeping.
GL with the team, Hope I Helped