1. Is Blissey a good Pokemon to use in OU?
Yes, she is the best special wall in the game.
2. Is she a good user of Counter?
Kind of, but Eviolite Chansey does that better.
3. Isn't Defense Curl,Softboiled,Seismic Toss and Refresh a good idea on her? I mean she can fix her low Def issue and Refresh is to heal status without needing to switch.
Defense Curl sucks and doesnt help with what switches into Blissey see: Pokemon with Fighting moves which she should just switch out of anyway, she shouldnt try and take on physical threats she is a team supporter and special wall. Refresh doesnt help either thanks to Natural Cure, plus Aromatherapy/Heal Bell outclass it as the heal the whole team. Regardless Blissey DOES need max def evs to stop weak phys attacks from mashing her, plus her HP and titanic special defense let her wall special attackers with hardly any investment well enough regardless.
The best sets for Blissey are the following;
Blissey@Leftovers
148 HP / 252 Def / 108 Sp.Def
Calm Nature
Trait: Natural Cure
~ Wish
~ Protect / Softboiled
~ Seismic Toss / Flamethrower
~ Toxic
Pass massive Wishes to the rest of your team. Activate Wish for yourself and stall for Toxic damage with Protect. Attacking move is up to you. If you use Flamethrower, put about 80 sp.att evs taken from HP to KO Scizor on the switch, Flamethrower also nails the steels immune to Toxic. Btw her sp.att isnt useless, its actually quite usable.
Blissey@Leftovers
148 HP / 252 Def / 108 Sp.Def
Calm Nature
Trait: Natural Cure
~ Aromatherapy / Stealth Rock
~ Softboiled
~ Seismic Toss / Flamethrower / Ice Beam
~ Toxic / Thunderwave
Same thing here except this is a more support oriented set. Aroma heals the whole team of Status whilst Stealth Rock is Stealth Rock and arguable the best move in the game and causes residual damage. Thunderwave slows things down whilst Ice Beam is an option for Gliscor and dragons.
Those following aren't questions concerning competitive battling but well, let me ask them since I have already opened up the topic :) Thank you good mods.
4. Is she difficult to find in Safari Zone and capture?
Yes lol.
5. Did you know that she can take physical hits just like Aipom and Mr.Mime, a bit worse(almost exactly the same though) than Raichu,Roserade and even better than Alakazam?
Wrong, with max defense Evs she can take hits as a Max HP Spritiomb and Scizor.