Power up question

I cannot think of any gym rework that makes your blissey worthless. IV93, ATT15, best defending moveset - without a doubt one of the very best defenders in game.

You could get problems, if you live in a very blissey-dominated region, if there comes a restriction to one blissey per gym. Then, you maybe will have a problem to find a place to put her, and you maybe would want to have saved your stardust for a less popular defender.

Only reason to wait that I can see is if there is a half candy/dust powerup event after gym rework...Since Chancey candy is more rare, you could save candies by waiting...

Since you can't use them after gyms are closed, can't hurt to wait I suppose.

The gyms are closing now, it's already announced, so I really see no reason not to wait until they reopen. Your Blissey won't do you much good without any gyms around.

Outside of that, congrats on your Blissey. If the new gym scene looks anything like the old, then a Blissey with that moveset and high IV's is the single best pokemon in the game, period.

Watch them eliminate dust and only power up through gym training. The people who saved a million in dust will be screaming.

Wait until the rework.

More than any other pokemon, I would hold off on powering blisseys. It's almost certain that "blissey towers" will be nerfed (via max pokemon in gym limit, almost certainly), but it's not unlikely that we'll see some other nerf to blissey as well. I personally think that blissey is fine as is, and one of the few worthy challenges in gym battle - the only problem with them is that there can be a gym full of the damned things. But who knows how Niantic feels about blissey.