Hi everyone. This is a set which I've been testing recently and has worked very well. From memory, Plus made it to the top of the CAP ladder using a similar set.
Healing Wish
Move 1: Healing Wish
Move 2: Softboiled
Move 3: Thunder Wave
Move 4: Seismic Toss
Item: Leftovers
Ability: Natural Cure
EV's: 252 HP / 252 Def / 4 Spe
Nature: Bold
Why this set should be on site
-Maintains Blissey's incredible specially defensive properties.
-Suited to offensive or balanced teams due to its ability to maintain momentum for the team (unlike most Blissey) and heal offensive members.
-The main strategy is to do as much damage with offensive pokemon as quickly as possible, while Blissey maintains a defensive backbone; then use Healing Wish to exploit the opponents weakened counters.
-Blissey lacks both Screens, unlike Lunar Dance Cresselia, but has vastly superior special walling capacity, recovery, Natural Cure, and lacks Cresselia's U-turn and Pursuit weaknesses. Blissey is also slower, meaning that it can usually take a hit THEN use Healing Wish, allowing the incoming pokemon to avoid taking damage.
Set Comments
-EV's and nature are standard, and maxed physical defense is necessary to get off a Healing Wish against powerful physical attackers.
-The 3rd and 4th slots are mainly personal preference, and there are a number of other options which can be used there, including Stealth Rock, Toxic and the like. However, Thunder Wave and Seismic Toss provide Blissey's best coverage against threats in 2 moves.
-Needs to be careful of a number of sweepers which can set up if they avoid Thunder Wave. Blissey shouldn't mind taking damage early in the game, so against offensive teams, don't give free turns away by trying to keep Blissey at high HP. Thunder Wave should be the main attack on predicted switches.
Teammates and Counters
-Has problems 1v1 with Fighting types and powerful physical attackers, such as Tyranitar, Taunt Gyarados, Machamp and others, so teammates which can deal with these pokemon, such as Gyarados and Hippowdon, are recommended.
-Incapable of hurting Substitute or Taunt versions of Rotom-A and Gengar unless it hits them with Thunder Wave on the switch, so teammates which can defeat or pseudohaze these pokemon are necessary.
-Offensively and defensively, Dragon Dance Gyarados is one of the best possible partners for this set, benefitting greatly from Healing Wish while also being capable of setting up on many physical attackers which switch into Blissey.
Right, think I got everything. Any suggestions would be great, thanks :)
Okay, I accept this isn't gonna get passed, and KG gave some decent reasoning. It's a very niche kind of role for the set and I suppose for a lot of teams its not going to be a better option than existing alternatives.

Healing Wish
Move 1: Healing Wish
Move 2: Softboiled
Move 3: Thunder Wave
Move 4: Seismic Toss
Item: Leftovers
Ability: Natural Cure
EV's: 252 HP / 252 Def / 4 Spe
Nature: Bold
Why this set should be on site
-Maintains Blissey's incredible specially defensive properties.
-Suited to offensive or balanced teams due to its ability to maintain momentum for the team (unlike most Blissey) and heal offensive members.
-The main strategy is to do as much damage with offensive pokemon as quickly as possible, while Blissey maintains a defensive backbone; then use Healing Wish to exploit the opponents weakened counters.
-Blissey lacks both Screens, unlike Lunar Dance Cresselia, but has vastly superior special walling capacity, recovery, Natural Cure, and lacks Cresselia's U-turn and Pursuit weaknesses. Blissey is also slower, meaning that it can usually take a hit THEN use Healing Wish, allowing the incoming pokemon to avoid taking damage.
Set Comments
-EV's and nature are standard, and maxed physical defense is necessary to get off a Healing Wish against powerful physical attackers.
-The 3rd and 4th slots are mainly personal preference, and there are a number of other options which can be used there, including Stealth Rock, Toxic and the like. However, Thunder Wave and Seismic Toss provide Blissey's best coverage against threats in 2 moves.
-Needs to be careful of a number of sweepers which can set up if they avoid Thunder Wave. Blissey shouldn't mind taking damage early in the game, so against offensive teams, don't give free turns away by trying to keep Blissey at high HP. Thunder Wave should be the main attack on predicted switches.
Teammates and Counters
-Has problems 1v1 with Fighting types and powerful physical attackers, such as Tyranitar, Taunt Gyarados, Machamp and others, so teammates which can deal with these pokemon, such as Gyarados and Hippowdon, are recommended.
-Incapable of hurting Substitute or Taunt versions of Rotom-A and Gengar unless it hits them with Thunder Wave on the switch, so teammates which can defeat or pseudohaze these pokemon are necessary.
-Offensively and defensively, Dragon Dance Gyarados is one of the best possible partners for this set, benefitting greatly from Healing Wish while also being capable of setting up on many physical attackers which switch into Blissey.
Right, think I got everything. Any suggestions would be great, thanks :)