I think a large contributor when people reminisce about the low damage of old season is actually Itempaths.
You need synergy in your Itembuilds to actually be a threat.
1. Adc was the only role that had hard synergizing Build paths with good items scaling off of each other
2. Midlane had to first fix mana issues and try to scrape together some cdr but had some decent items and synergies as well
3. Jungle was a mess, and item paths especially sucked, ap jungling was especially hard,
4. Top Lane was completly insane (if you could not use trinity force) with people regularly building **Wriggles Lantern** the jungle item into full tank since there were at some point no offensive options, this applied also to alot of junglers
5. Support: There was actually no item builds , supports spent all their gold for wards and gold generation
So this leaves us with: Only adc doing any realistic damage, in some cases mages as well.
Support being a complete non factor damage wise, and that actually makes a lot of sense when you see complaints about damage, there is basically 1 whole player more to worry about today.
The difference gets even greater when you consider that regularly top lane and jungler would not do any damage and be super tanky
Today, items give every class exactly the stats they want, the damage is the same now as it couldve been back then, if people had access to good items.
I dont really know what to make of this, but this seems to me like the biggest factor, and why Riot has problems communicating and solving the issues right now. You cant really go back on these changes, making items worse and buying stats you dont really want isnt really something that players want. Or what do you guys think?