Some questions about gameplay changes for a past few years

I'm pretty old player, I remember times, when 4 element Legendaries was the strongest and coolest thing. Like a lot of players I comeback to this game from time to time, usually every few years, and at this time I played like for few weeks. A lot has changed, and Heroic dragons now very easy to obtain and regular ones is not this good anymore, Races definitely more easy now, I didn't remember back then that I can go for 18 lap so easy. And a lot more.

So I have a few questions:

— Did new cool powerful dragons can be obtained thro races? And did they really changed how it works? I don't know am I shizo or not.

— Did this new sticker collection thing is rigged? I swear I got less unique stickers in this collection then in previous that I played for a week or smt.

— How is trading working? Did it only works within clan (mine is pretty dead for past 10 years or smt, lol.

— What else should I know? Perk thing really confused me for a moment but I think I got it now.