Hi there! Nice team here!
The first thing I suggest is to Insert Deoxys-D > Ferrothorn
This is an Hyper Offence team and ferrothorn slow down your team losing momentum.
The hazards for the HO teams are very important because they allow your sweepersu to reach the opponent's KO range so you have to be sure to put on the field the most number of hazards just to facilitate the sweep of your Pokémon.
Ferrothorn can become easily a set-up fodder for opponent while setting the hazards and if the opponent boost himself too much could really hard to stop it running the risk that he make big damages in your team, but with deoxys, his speed and his support moves allows you to set the hazards on the ground at the same time prevent the opponent boost himself.
The set that i always recommend is: Four support moves @RedCard to be able to put on the field the greatest number of hazard than other deoxys also thanks to the combo RedCard-Taunt prevents that the opponent uses Deoxys as a set-up fodder 'cause with taunt blocks that opponent boosting himself and red card force his switch if use an offensive move, last slot is magic coat that prevents fastest taunter prevent you from placing the hazards.
The second thing I notice is that your team haven't a Wallbreaker so the stall team can give you some problems, to solve it I want to recommend a quick change of Thundurus
: I want to make him double boost.
Making him double boost
you'll get a huge versatility that will adapt well to any team that will find:
if you have to fight against a stall will be sufficient to use nastyplot to create huge holes in the opposing team with excellent coverage Electric-Ice which will hit all Pokémon present in the stall at the same time if you have to fight against an offensive team is enaugh will use agility to make your speed double so that no one can outspeed you and can cleanare the opposing team.
The cherry on the cake is the Yache berry.
With the Yache berry to halve the power of Mamoswine's iceshard taking a half damage in such a way that does not interrupt your sweep.
In essence doubleboost Thundurus is a really versatile monster.
The last thing I want to advise is a little quick change that will prove very useful.
I'm talking about to put Psyshock > Psychic on Starmie
With Psyshock you can hit from the physical side and will come in handy especially against CalmMind Keldeo, Amoonguss and Terrakion in sand because it would have special defense boosted and would go to take a reduced damage from scald.
Psyshock have another important role: can make more damage on Tentacruel; is important to kill Cruel very quickly 'cause he can spin your hazards!