Your strategy will have 3 crippling weaknesses.
1) A single Rapid Spin will hurt your strategy significantly.
Given the members of your team, this is likely not a crippling deficiency. However, 1 use of Rapid Spin will remove all entry hazards on the opponents field. Which leads into...
2) "Switching" moves will always go last
Dragon Tail, like other moves that force the opponent to switch Pokemon, are in the lowest priority bracket at -6. Each bracket is the resolved in Speed order before moving down to the next one. So your Dragon Tail force switchers will be moving after their targets, ensuring that the opponent gets an attack in. This also makes you unbelievably vulnerable to Ice attacks, which every one of your switchers (except Hydreiggon) has a 4x weakness to. While it's unlikely that any of your Dragons will be 1HKO'd, they will certainly take significant damage from a single Ice Beam or even the low powered Ice Shard. Nevermind Icicle Crash. Finally....
3) A single Fairy will ruin you
This may not apply directly to you, because you are in Gen 5 before the Fairy type was added, however, it would be somewhat foolish to completely ignore this point.
In fact, the other moves on all of your switchers DO matter, because Fairy type is immune to Dragon type. Not only will you do no damage to a Fairy, but you will also not force the switch for your entry hazards. The obvious way around this is to make sure all of your switchers have a move that is Poison or Steel with moderate to high power in order to take them down.