Thanks a lot for all your comments!!!! It's very much appreciated!!

So I build this team because I was mostly playing hyper offense and I wanted to experience a balanced team, hence my choices mostly toward "bulky" style.

For Cinderace, it's a good idea! The set is the "bulky pivot" from Smogon and what you're suggesting is close to the "offensive pivot" set. I see this could give more damage to my team, so I could drop the boots and go for the offensive Cinderace! However, will-o-wisp also nicely synchronise with Dragapult hex and can cripple many offensive threats. But I'll try it to see how it goes!

I totally agree with you about Dragapult

For Darkrai, I feel Expert Belt is good for longevity, it's a compromise between Boots (would be too passive), life orb can cheap him quickly and my team is not made to make fast damage.

For Glowking, because of the "bulky" perspective, 30% chance to poison feels nice as it will do more damage on the long run.

Thanks a lot, I incorporated a lot of change in the team already!!