More than 3000 CP Blissey

Before the Valentine's Day event, Chansey can be just as rare as Lapras. Requiring 400 candies or more would be ridiculous. There are Magikarps everywhere so requiring 400 for Gyarados is reasonable

Some legit people didn't even manage to have 50 candies because they are not using trackers...

Then the problem is the ingame radar that might need an update... Sometimes you walk near a snorlax and you don't even kno there is one next to you because the radar shows a pidgey in the pokestop...

We should be able to filter pokemons we want to see in pokestops, because there are too many pokemons we don't want to see anymore because we can find them everywhere.
The it makes targetting Chansey more easily, and maybe you can consider that 50 candies is not enough.
But trust me, 50 candies for the moment is kind of balanced for the moment, I would say.

The way to take down a high CP Blissey is to attack as a team. Not sure if this is on purpose, but Niantic may be trying to encourage team play. I took one down yesterday with a team of 3 and it was pretty fun :-)

If you are below level 30, you probably will have to have help to defeat a Blissey of that level. You can defeat one solo, but you will need a Pokemon with a high CP AND DPS (determined by move set). Their is a list of Highest DPS by Type on this page but it hasn't been updated yet. I'm sure it will soon though. A high CP espeon with Confusion and Future Sight could probably do it (and would resist a Blissey with Psychic type moves). Also, a high CP pokemon with strong fighting type moves (new Poliwrath with Rock Smash and Dynamic Punch, Heracross with Counter and Close Combat) will give you more boost, HOWEVER, if they are fighting type (best because of the STAB bonus) then they are vulnerable to a Psychic move set Blissy.

The V-day event certainly changed the availability of Chansey...Not using trackers, they were all over desert biomes and you'd find 3 on nearby even.

I hatched 2 prior to the event and had over 130 candies before the v-day event due to double candy Halloween hatches and walking nearly 200km...

It certainly is a pain mon to defeat without good fighting mons, but Machamp is now a beast against it with his new moveset so if you can evolve a Machop, Blissey isn't as scary anymore...

Time to look for Machop nests.