Class selection question!

bringing some context i am a mythci raider and mythic+ enjoyer and also a break the meta #1 from my server and 4rth on americas that being said when i played cata it was my frist expantion during the last weeks of firelands and dragonsoul some people say its bad some people say it was hard, i honestly want to play it from the start at 60 fps this time and during my precius cata times all i did was hang out with friends on dungeon finder and LFR which for me was the greatest experience ever to let new players see the final cutscene.

  • which class do you think has the most potential to get into groups for raiding 10 man between rogue (playing combat and assasination depending on encounter) paladin (playing ret-holy for raids and prot for dungeons) or warlock (demonology-Affliction)?

  • how does gamma/beta/mythic + works on classic?

  • which class do you think has the most potential to get into groups for raiding 25 man between rogue (playing combat and assasination depending on encounter) paladin (playing ret-holy for raids and prot for dungeons) or warlock (demonology-Affliction)?

i honestly dont know if buff stacking its a thing from the past or not i did some research and alot of world first were done with class stacking and wierd shenanigans like summoning people middle of the encounter; in Retail a good staple for raiding its Mage, lock and dh, is there such thing as staples in 10 man?

sorry for the wall of text as leveling takes awhile i want to only level what would not be a meme class even if its not the strongest i dont have a problem, my problem would be if the class its literally dogwater like ret paladins on classic wow.