Retail is honestly way easy too play , compared to custom.
Most of us have played it on the past. Difference beeing , we don't go to some Retail server posting our videos about how good we are and how we are 10 years ahed of them , and then refuse to actually play it and back up our words ^
I feel like custom is much easier than retail (pre 1.5.1 at least)
Mage is so much easier here cause of the fast heal, a lot of chi and 120 dex genie + vit/mag genie that can get like all skills...Especially in MG vs MG you can just spam hiero bug combos and eventually you might win by luck which wasn't possible on retail where you had to work hard to hiero bug anyone cause of def charms and slow cast.
EA seems much easier with the channeling too, sins are just aps monkeys who can script to change to full def gear (on retail you had only 1 r9 set)
Support classes survive more because of the genie and insane def.
I feel like epic only looks harder to play on paper cause of the higher damage, if you think of scripting and higher LP genies I feel like epic is easier.
PW is getting easier with every version though so it doesn't matter